Researcher Profile and Settings

Master

Affiliation (Master)

• Faculty of Dental Medicine　Division of Dental Medicine　Department of Health Science

Affiliation (Master)

• Faculty of Dental Medicine　Division of Dental Medicine　Department of Health Science

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Profile and Settings

Degree

• Doctor (Engineering)（Nagoya University）

Profile and Settings

• Name (Japanese)

  AKASAKA

• Name (Kana)

  Tsukasa

• Name

  200901028498894860

Alternate Names

http://www.den.hokudai.ac.jp/seitaizairyou/akasaka/

Achievement

Research Interests

• Cell culture   Micro/nano pattern   Nanoimprint   ナノインプリント   マイクロ・ナノパターン   歯科理工学   分化誘導   パターニング   スキャホールド   骨芽細胞   チタン   カーボンナノチューブ   糖鎖工学   Nanotechnology   Dental materials   

Research Areas

• Life sciences / Biomaterials
• Life sciences / Biomedical engineering
• Nanotechnology/Materials / Nanobioscience
• Life sciences / Regenerative dentistry and dental engineering
• Life sciences / Prosthodontics

Research Experience

• 2011/09 - Today 北海道大学 歯学研究科(研究院) 准教授
• 2011/09 Hokkaido University Graduate School of Dental Medicine Associate Professor
• 2007/04 - 2011/08 - 北海道大学大学院歯科研究科 助教
• 2007/04 - 2011/08 Hokkaido University Graduate School of Dental Medicine Assistant Professor
• 2002/12 - 2006/03 北海道大学大学院歯科研究科 助手
• 2002/12 - 2006/03 Hokkaido University Greduate school of Deantal Medicine Research Assistant
• 2000/06 - 2002/11 株式会社生物有機化学研究所 研究員
• 2000/06 - 2002/11 Chemical Biological Institute Researcher

Education

• 1997/04 - 2000/03  Nagoya University
•        - 2000  Nagoya University  Graduate School, Division of Engineering  Department of Molecular Design and Enginnering
• 1995/04 - 1997/03  Hokkaido University
• 1991/04 - 1995/03  Meiji University  School of Science and Technology
•        - 1995  Meiji University  Faculty of Science and Engineering  Department of Industrial Chemistry

Awards

• 2015/10 日本歯科医学会 第31回「歯科医学を中心とした総合的な研究を推進する集い」優秀発表賞
   「歯表面での3D微細構造構築によるバイオミメティック次世代歯科治療へ向けて」 

  受賞者: 赤坂 司
• 2013/10 日本歯科理工学会 第６１回日本歯科理工学会 発表優秀賞
   「マイクロ・ナノ構造を持つパターン化バイオマテリアルの調製」 

  受賞者: 赤坂 司
• 2008/12 "Materials Science and Engineering C" Most Cited Author Award 2005-2008.
   Title: "Apatite formation on carbon nanotubes" T.Akasaka, F.Watari, Y.Sato, K.TohjiMaterials Science and Engineering C, 26(4), 675-678 (2006).
• 2006/10 日本歯科理工学会 第48回 日本歯科理工学会 研究奨励賞
   「人工複合糖質高分子によるStreptococcus mutansの増殖阻害」
• 2006 Molecular Biosystems Cover Gallery Winner 2005
  
• 2004/10 傾斜機能材料研究会 傾斜機能材料シンポジウム FGM奨励賞
   「糖鎖によるカーボンナノチューブの表面修飾」 

  受賞者: 赤坂 司

Published Papers

• Synthesis and evaluation of fluorescent resins with europium-β-diketonate complex for orthodontic use

  Shuichi YAMAGATA, Takaaki YAMAMOTO, Yoshiaki SATO, Tsukasa AKASAKA, Yasuhiro YOSHIDA

  Dental Materials Journal 43 (4) 531 - 538 0287-4547 2024/07/25
• From Tooth Adhesion to Bioadhesion: Development of Bioabsorbable Putty-like Artificial Bone with Adhesive to Bone Based on the New Material "Phosphorylated Pullulan".

  Ko Nakanishi, Tsukasa Akasaka, Hiroshi Hayashi, Kumiko Yoshihara, Teppei Nakamura, Mariko Nakamura, Bart Van Meerbeek, Yasuhiro Yoshida

  Materials (Basel, Switzerland) 17 (15) 2024/07/25 

  Bioabsorbable materials have a wide range of applications, such as scaffolds for regenerative medicine and cell transplantation therapy and carriers for drug delivery systems. Therefore, although many researchers are conducting their research and development, few of them have been used in clinical practice. In addition, existing bioabsorbable materials cannot bind to the body's tissues. If bioabsorbable materials with an adhesive ability to biological tissues can be made, they can ensure the mixture remains fixed to the affected area when mixed with artificial bone or other materials. In addition, if the filling material in the bone defect is soft and uncured, resorption is rapid, which is advantageous for bone regeneration. In this paper, the development and process of a new bioabsorbable material "Phosphorylated pullulan" and its capability as a bone replacement material were demonstrated. Phosphorylated pullulan, which was developed based on the tooth adhesion theory, is the only bioabsorbable material able to adhere to bone and teeth. The phosphorylated pullulan and β-TCP mixture is a non-hardening putty. It is useful as a new resorbable bone replacement material with an adhesive ability for bone defects around implants.
• Epithelial-mesenchymal transition in oral cancer cells induced by prolonged and persistent Fusobacterium nucleatum stimulation

  Shintaro Nakano, Machiko Kasai, Keisuke Nakamura, Tsukasa Akasaka, Yasuhiro Yoshida, Shiho Suzuki, Yoichi Ohiro, Akira Hasebe

  Journal of Oral Biosciences 1349-0079 2024/05
• Investigation of a new implant surface modification using phosphorylated pullulan.

  Kanako Nagamoto, Ko Nakanishi, Tsukasa Akasaka, Shigeaki Abe, Kumiko Yoshihara, Mariko Nakamura, Hiroshi Hayashi, Shinji Takemoto, Masato Tamura, Yoshimasa Kitagawa, Bart Van Meerbeek, Yasuhiro Yoshida

  Frontiers in bioengineering and biotechnology 12 1378039 - 1378039 2024 

  Various implant surface treatment methods have been developed to achieve good osseointegration in implant treatment. However, some cases remain impossible to treat with implants because osseointegration is not obtained after implantation, and the implants fail. Thus, this study focused on phosphorylated pullulan because of its adhesiveness to titanium (Ti) and bone, high biocompatibility, and early replacement with bone. In this study, the response of bone-related cells to phosphorylated pullulan was evaluated to develop a new surface treatment method. Saos-2 (human osteosarcoma-derived osteoblast-like cells), MC3T3-E1 (mouse calvaria-derived osteoblast-like cells), and RAW264.7 (mouse macrophage-like cells) were used. In evaluating cellular responses, phosphorylated pullulan was added to the culture medium, and cell proliferation and calcification induction tests were performed. The proliferation and calcification of cells on the surface of Ti disks coated with phosphorylated pullulan were also evaluated. In addition, bone morphogenetic protein-2 (BMP-2), an osteogenic factor, was used to evaluate the role of phosphorylated pullulan as a drug carrier in inducing calcification on Ti disks. Phosphorylated pullulan tended to promote the proliferation of osteoblast-like cells and the formation of calcification on Ti disks coated with phosphorylated pullulan. Ti disks coated with phosphorylated pullulan loaded with BMP-2 enhanced calcification. Phosphorylated pullulan inhibited osteoclast-like cell formation. These results are due to the properties of phosphorylated pullulan, such as adhesiveness to titanium and drug-loading function. Therefore, phosphorylated pullulan effectively promotes bone regeneration when coated on titanium implants and is useful for developing a new surface treatment method.
• 微細構造に応答した破骨細胞が作り出す多様なアクチン構造物

  赤坂 司, 中西 康, 吉田 靖弘

  日本歯科理工学会誌 (一社)日本歯科理工学会 42 (Special Issue WINTER) 5 - 5 1884-4421 2023/12
• 破骨細胞様細胞による凹凸基材に応答したアクチン構造物の形成

  赤坂 司, 宮治 裕史, 横山 敦郎, 吉田 靖弘

  日本バイオマテリアル学会大会予稿集 日本バイオマテリアル学会 45回 422 - 422 2023/10
• 破骨細胞様細胞による凹凸基材に応答したアクチン構造物の形成

  赤坂 司, 宮治 裕史, 横山 敦郎, 吉田 靖弘

  日本バイオマテリアル学会大会予稿集 日本バイオマテリアル学会 45回 422 - 422 2023/10
• In vivo transmission electron microscopy of the alternating structure of the protrusions between adjacent macrophage-like cells on micropatterns.

  Natsumi Ushijima, Tsukasa Akasaka, Shinichiro Numamoto, Tsubura Kudo, Atsuro Yokoyama

  Journal of oral biosciences 2023/06/29 

  OBJECTIVES: We investigated the behavior of macrophages in the defined microtopography of materials. METHODS: Patterned cyclo-olefin polymer films were implanted into the femurs of seven-week-old rats. After 1 and 4 weeks, the rats were fixed with glutaraldehyde and OsO4, and their bones were observed with transmission electron microscopy (TEM). RESULTS: TEM and segmentation revealed an alternating structure in which multiple protrusions of adjacent macrophage-like cells overlapped. They were approximately 2 μm long and almost uniform in width, and were induced by the limited topography. CONCLUSION: New structures appeared between the macrophage-like cells as a result of microtopography.
• Can a low dosage of recombinant human bone morphogenetic protein-2 loaded on collagen sponge induce ectopic bone?

  Mohammed Katib Alruwaili, Tsutomu Sugaya, Yasuhito Morimoto, Ko Nakanishi, Tsukasa Akasaka, Yasuhiro Yoshida

  Dental materials journal 42 (3) 433 - 440 2023/04/07 

  Recombinant human bone morphogenetic protein-2 (rhBMP-2) is one of the growth factors that may induce the formation of new bone. The aim was to determine the efficacy of low doses of rhBMP-2 for bone regeneration using a collagen sponge as a carrier. Three doses of rhBMP-2 (1.167, 0.117, and 0.039 mg/mL) were combined with an absorbable collagen sponge (ACS) as a delivery vehicle. The rhBMP-2/ACS implants were placed in the subcutaneous tissues of rat backs. X-ray microcomputed tomography (micro-CT) and histological analysis were used to evaluate bone formation. The samples treated with 1.167 mg/mL of rhBMP-2 showed greater bone formation than the samples treated with 0.117 mg/mL of rhBMP-2 four weeks after surgery. However, there was no evidence of bone formation in the samples that were treated with 0.039 mg/mL of rhBMP-2. It was found that rhBMP-2 was osteogenic even at one-tenth of its manufacturer's recommended concentration (1.167 mg/mL), indicating its potential for clinical use at lower concentrations.
• ヒトI型コラーゲン様リコンビナントペプチド/β-三リン酸カルシウム骨補填材による歯周組織再生効果

  吉野 友都, 宮治 裕史, 西田 絵利香, 金本 佑生実, 浜本 朝子, 加藤 昭人, 菅谷 勉, 赤坂 司

  日本歯周病学会会誌 (NPO)日本歯周病学会 65 (春季特別) 133 - 133 0385-0110 2023/04
• ヒトI型コラーゲン様リコンビナントペプチド/β-三リン酸カルシウム骨補填材による歯周組織再生効果

  吉野 友都, 宮治 裕史, 西田 絵利香, 金本 佑生実, 浜本 朝子, 加藤 昭人, 菅谷 勉, 赤坂 司

  日本歯周病学会会誌 (NPO)日本歯周病学会 65 (春季特別) 133 - 133 0385-0110 2023/04
• 破骨細胞分化へのパターン材質と前駆細胞種の影響

  赤坂 司, 中西 康, 吉田 靖弘

  日本歯科理工学会誌 (一社)日本歯科理工学会 42 (Special Issue81) 78 - 78 1884-4421 2023/03
• Development of Autopolymerizing Resin Material with Antimicrobial Properties Using Montmorillonite and Nanoporous Silica

  Shuhei Otsubo, Ko Nakanishi, Kakufu Fukukawa, Ryoshun Endo, Seiichiro Yoshida, Aiko Matsumoto, Kumiko Yoshihara, Tsukasa Akasaka, Akira Hasebe, Yasuhiro Yoshida, Yoshiaki Sato

  Pharmaceutics 15 (2) 544 - 544 2023/02/06 

  Although autopolymerizing resin offers numerous applications in orthodontic treatment, plaque tends to accumulate between the appliance and the mucosa, which increases the number of microorganisms present. In this study, we added cetylpyridinium chloride (CPC) loaded montmorillonite (Mont) and nanoporous silica (NPS) to autopolymerizing resin (resin-Mont, resin-NPS) and evaluated their drug release capacity, antimicrobial capacity, drug reuptake capacity, mechanical strength, and color tone for the devolvement of autopolymerizing resin with antimicrobial properties. As observed, resin-Mont and resin-NPS were capable of the sustained release of CPC for 14 d, and a higher amount of CPC was released compared to that of resin-CPC. Additionally, resin-Mont and resin-NPS could reuptake CPC. Moreover, the antimicrobial studies demonstrated that resin-Mont and resin-NPS could release effective amounts of CPC against Streptococcus mutans for 14 d and 7 d after reuptake, respectively. Compared to resin-CPC, resin-Mont exhibited a higher sustained release of CPC in all periods, both in the initial sustained release and after reuptake. However, the mechanical strength decreased with the addition of Mont and NPS, with a 36% reduction observed in flexural strength for resin-Mont and 25% for resin-NPS. The application of these results to the resin portion of the orthodontic appliances can prevent bacterial growth on the surface, as well as on the interior, of the appliances and mitigate the inflammation of the mucosa.
• Periodontal tissue regeneration by recombinant human collagen peptide granules applied with β-tricalcium phosphate fine particles.

  Yuto Yoshino, Hirofumi Miyaji, Erika Nishida, Yukimi Kanemoto, Asako Hamamoto, Akihito Kato, Tsutomu Sugaya, Tsukasa Akasaka

  Journal of oral biosciences 2023/01/17 

  OBJECTIVES: Recombinant human collagen peptide (RCP) is a recombinantly created xeno-free biomaterial enriched in arginine-glycine-aspartic acid sequences with good processability whose use for regenerative medicine applications is under investigation. The biocompatibility and osteogenic ability of RCP granules combined with β-tricalcium phosphate (TCP) submicron particles (β-TCP/RCP) were recently demonstrated. In the present study, β-TCP/RCP was implanted into experimental periodontal tissue defects created in beagles to investigate its regenerative effects. METHODS: An RCP solution was lyophilized, granulated, and thermally cross-linked into particles approximately 1 mm in diameter. β-TCP dispersion (1 wt%; 500 μL) was added to 100 mg of RCP granules to form β-TCP/RCP. A three-walled intrabony defect (5 mm × 3 mm × 4 mm) was created on the mesial side of the mandibular first molar and filled with β-TCP/RCP. RESULTS: A micro-computed tomography image analysis performed at 8 weeks postoperative showed a significantly greater amount of new bone after β-TCP/RCP grafting (2.2-fold, P<0.05) than after no grafting. Histological findings showed that the transplanted β-TCP/RCP induced active bone-like tissue formation including tartaric acid-resistant acid phosphatase- and OCN-positive cells as well as bioabsorbability. Ankylosis did not occur, and periostin-positive periodontal ligament-like tissue formation was observed. Histological measurements performed at 8 weeks postoperative revealed that β-TCP/RCP implantation formed 1.7-fold more bone-like tissue and 2.1-fold more periodontal ligament-like tissue than the control condition and significantly suppressed gingival recession and epithelial downgrowth (P<0.05). CONCLUSIONS: β-TCP/RCP implantation promoted bone-like and periodontal ligament-like tissue formation, suggesting its efficacy as a periodontal tissue regenerative material.
• 温度応答性歯科矯正用解体性接着材の開発

  春藤 彩花, 中西 康, 金子 知生, 黒川 考幸, 松本 愛子, 遠藤 諒俊, 赤坂 司, 吉田 靖弘, 佐藤 嘉晃

  日本矯正歯科学会大会プログラム・抄録集 (公社)日本矯正歯科学会 81回 177 - 177 2022/10
• Extracted tissue-specific atelocollagens have distinctive textural properties.

  Sayaka Nakamura, Hiroko Hoshi, Kaito Wakabayashi, Manami Seki, Makoto Watanabe, Momoka Watanabe, Hiroki Inaba, Natsumi Ushijima, Tsukasa Akasaka

  Journal of texture studies 53 (5) 654 - 661 2022/09 [Refereed]
   

  Food texture is a very important factor for elderly persons, children, and patients who have difficulty swallowing. Collagen and its hydrolysis product, gelatin, are used as ingredients in foods, dietary supplements, and medical materials. In this study, we extracted atelocollagen from nonedible porcine tissues, including ear, nose, and skin, and analyzed the biophysical properties of each tissue. Extracted whole auricle collagen (AEC) showed superior springiness, while only the skin region of auricle collagen (ASC) showed superior hardness, springiness, and brittleness. Body skin collagen showed high hardness but low springiness. In a shear stress test, ASC gels showed high shear strength, and their strains coincided with hardness in a textural examination, while nose and AEC showed low maximum strains. In viscosity, the auricular collagens showed higher viscosity regardless of the region of the ear. Fibril formation in collagen from each tissue and organ varied a great deal in width and morphology. We found that the same type of collagen had a unique texture and viscosity under physiological conditions depending on the tissue or organ of extraction. The results show that the collagen extracted from each organ has a unique texture and unique possibilities to serve as an ingredient in food or supplements.
• 前駆体利用バイオミメティックプロセスによる低結晶性アパタイト成膜足場材 骨・歯周組織形成能の評価

  金本 佑生実, 宮治 裕史, 西田 絵利香, 宮田 さほり, 眞弓 佳代子, 吉野 友都, 加藤 昭人, 菅谷 勉, 赤坂 司, 大矢根 綾子

  日本歯周病学会会誌 (NPO)日本歯周病学会 64 (秋季特別) 122 - 122 0385-0110 2022/08
• Surface pre-reacted glass-ionomer(S-PRG)ナノフィラー分散液を注水に用いた超音波スケーラーによる歯周炎改善効果

  宮治 裕史, 眞弓 佳代子, 金本 佑生実, 岡本 一絵, 浜本 朝子, 加藤 昭人, 菅谷 勉, 赤坂 司, 田中 佐織

  日本歯周病学会会誌 (NPO)日本歯周病学会 64 (秋季特別) 126 - 126 0385-0110 2022/08
• Ultrasonic irrigation of periodontal pocket with surface pre-reacted glass-ionomer (S-PRG) nanofiller dispersion improves periodontal parameters in beagle dogs.

  Hirofumi Miyaji, Kayoko Mayumi, Yukimi Kanemoto, Ichie Okamoto, Asako Hamamoto, Akihito Kato, Tsutomu Sugaya, Tsukasa Akasaka, Saori Tanaka

  Journal of oral biosciences 64 (2) 222 - 228 2022/06 [Refereed]
   

  OBJECTIVES: Surface pre-reacted glass-ionomer (S-PRG) nanofiller, an antibacterial ion-releasing bioactive glass, has been shown to adhere to tooth surfaces and reported to improve inflammatory parameters in experimental periodontitis. In this study, cementum substrate was irrigated ultrasonically with dispersion to examine in-vitro nanofiller adhesion and antibacterial activity. Moreover, periodontal pockets in a beagle dog were ultrasonically irrigated with dispersion to assess periodontal healing. METHODS: The morphology of human cementum irrigated with S-PRG nanofiller dispersion was examined by scanning electron microscopy and energy dispersive X-ray spectrometry. The antibacterial activity of the treated cementum was tested using Actinomyces naeslundii. In addition, experimentally formed periodontal pockets in beagle dog were ultrasonically irrigated with S-PRG nanofiller dispersion. Periodontal parameters (gingival index, bleeding on probing, probing pocket depth, and clinical attachment level) were measured from baseline (0 weeks) through 12 weeks. Moreover, the effects of irrigation with S-PRG nanofiller on changes in periodontal microflora and bone healing were analyzed. RESULTS: After ultrasonic irrigation, S-PRG nanofiller adhered to the cementum and exhibited antibacterial activity. The periodontal parameters were shown to improve following ultrasonic irrigation with S-PRG nanofiller dispersion. Analysis by next-generation sequencing revealed that the ratio of red-complex species decreased in the pockets irrigated with S-PRG nanofiller dispersion. In addition, the S-PRG nanofiller showed the potential to promote bone healing. CONCLUSIONS: Ultrasonic irrigation with S-PRG nanofiller dispersion using an ultrasonic scaler system permitted delivery of the S-PRG nanofiller to the root surface, providing improved parameters in experimental periodontitis and modifying the composition of subgingival periodontal microflora.
• Osteoclast formation from mouse bone marrow cells on micro/nano-scale patterned surfaces.

  Tsukasa Akasaka, Hiroshi Hayashi, Miho Tamai, Yoshitaka Yoshimura, Yoh-Ichi Tagawa, Hirofumi Miyaji, Ko Nakanishi, Yasuhiro Yoshida

  Journal of oral biosciences 64 (2) 237 - 244 2022/06 [Refereed]
   

  OBJECTIVES: Osteoclasts can sense the surface topography of materials. However, it is difficult to identify the structural factors that affect osteoclast formation and its function. Furthermore, we hypothesized that the type of osteoclast precursor cells also affects osteoclastogenesis in the materials. In this study, we investigated the effects of defined micro/nanoscale patterns on osteoclastogenesis from bone marrow cells (BMCs). METHODS: Various cyclo-olefin polymer (COP) patterns were prepared using nanoimprinting. The effects of shape, size, and height of the patterns, and the wettability of the patterned surfaces on osteoclastogenesis from BMCs were evaluated in vitro. RESULTS: Osteoclast formation was promoted on pillars (diameter, 1 μm or 500 nm; height, 500 nm). Notably, osteoclastogenesis from BMCs was better promoted on hydrophobic pillars than on hydrophilic pillars. In contrast, decreased osteoclast formation was observed on the nanopillars (diameter, 100 nm; height, 200 nm). CONCLUSIONS: We demonstrated the promotion of osteoclast formation from BMCs on hydrophobic pillars with diameters of 1 μm and 500 nm. Some cellular behaviors in the patterns were dependent on the type of osteoclast precursor cells. The designed patterns are useful for designing the surface of dental implants or bone replacement materials with a controllable balance between osteoblast and osteoclast activities.
• Different micro/nano-scale patterns of surface materials influence osteoclastogenesis and actin structure

  Tsukasa Akasaka, Miho Tamai, Yoshitaka Yoshimura, Natsumi Ushijima, Shinichiro Numamoto, Atsuro Yokoyama, Hirofumi Miyaji, Ryo Takata, Shuichi Yamagata, Yoshiaki Sato, Ko Nakanishi, Yasuhiro Yoshida

  NANO RESEARCH 1998-0124 2022/01 [Refereed]
   

  The surface topography of a material can influence osteoclast activity. However, the surface structural factors that promote osteoclast activity have not yet been investigated in detail. Therefore, we investigated osteoclastogenesis by testing various defined patterns with different dimensions and shapes. The systematic patterns, made of a cyclo-olefin polymer, were prepared at a micron-, submicron-, and nano-scale with a groove, hole, or pillar shape with a 1:1 pitch ratio. RAVV264.7 cells were cultured on these patterns in the presence of the receptor activator of NF-kappa B ligand (RANKL). Osteoclast formation was induced in the order: pillar > groove >= hole. The two-dimensional factors also indicated that submicron-sized patterns strongly induced osteoclast formation. The optimal pillar dimension for osteoclast formation was 500 nm in diameter and 2 mu m in height Furthermore, we observed two types of characteristic actin structure, i.e., belt-like structures with small hollow circles and isolated ring-like structures, which formed on or around the pillars depending on size and height. Furthermore, resorption pits were observed mainly on the top of calcium phosphate-coated pillars. Thus, osteoclasts prefer convex shapes, such as pillars for differentiation and resorption. Our results indicate that osteoclastogenesis can be controlled by designing surfaces with specific morphologies.
• Periodontal tissue engineering using an apatite/collagen scaffold obtained by a plasma- and precursor-assisted biomimetic process.

  Yukimi Kanemoto, Hirofumi Miyaji, Erika Nishida, Saori Miyata, Kayoko Mayumi, Yuto Yoshino, Akihito Kato, Tsutomu Sugaya, Tsukasa Akasaka, Arputharaj Joseph Nathanael, Syama Santhakumar, Ayako Oyane

  Journal of periodontal research 57 (1) 205 - 218 2021/11/16 [Refereed]
   

  BACKGROUND AND OBJECTIVES: In the treatment of severe periodontal destruction, there is a strong demand for advanced scaffolds that can regenerate periodontal tissues with adequate quality and quantity. Recently, we developed a plasma- and precursor-assisted biomimetic process by which a porous collagen scaffold (CS) could be coated with low-crystalline apatite. The apatite-coated collagen scaffold (Ap-CS) promotes cellular ingrowth within the scaffold compared to CS in rat subcutaneous tissue. In the present study, the osteogenic activity of Ap-CS was characterized by cell culture and rat skull augmentation tests. In addition, the periodontal tissue reconstruction with Ap-CS in a beagle dog was compared to that with CS. METHODS: The plasma- and precursor-assisted biomimetic process was applied to CS to obtain Ap-CS with a low-crystalline apatite coating. The effects of apatite coating on the scaffold characteristics (i.e., surface morphology, water absorption, Ca release, protein adsorption, and enzymatic degradation resistance) were assessed. Cyto-compatibility and the osteogenic properties of Ap-CS and CS were assessed in vitro using preosteoblastic MC3T3-E1 cells. In addition, we performed in vivo studies to evaluate bone augmentation and periodontal tissue reconstruction with Ap-CS and CS in a rat skull and canine furcation lesion, respectively. RESULTS: As previously reported, the plasma- and precursor-assisted biomimetic process generated a low-crystalline apatite layer with a nanoporous structure that uniformly covered the Ap-CS surface. Ap-CS showed significantly higher water absorption, Ca release, lysozyme adsorption, and collagenase resistance than CS. Cell culture experiments revealed that Ap-CS was superior to CS in promoting the osteoblastic differentiation of MC3T3-E1 cells while suppressing their proliferation. Additionally, Ap-CS significantly promoted (compared to CS) the augmentation of the rat skull bone and showed the potential to regenerate alveolar bone in a dog furcation defect. CONCLUSION: Ap-CS fabricated by the plasma- and precursor-assisted biomimetic process provided superior promotion of osteogenic differentiation and bone neoformation compared to CS.
• リゾチーム-金ナノクラスター/ローズベンガル複合体の抗菌・抗バイオフィルム光線力学的活性

  岡本 一絵, 宮治 裕史, 宮田 さほり, 菅谷 勉, 蔀 佳奈子, 赤坂 司, 齋田 慧, 川崎 英也

  日本歯周病学会会誌 (NPO)日本歯周病学会 63 (秋季特別) 133 - 133 0385-0110 2021/10 [Not refereed]
  
• S-PRGナノフィラーを用いた抗菌性歯面コーティングによる臨床パラメーターの改善 イヌ実験的歯周炎における検討

  眞弓 佳代子, 宮治 裕史, 宮田 さほり, 西田 絵利香, 降旗 友和, 金本 佑生実, 菅谷 勉, 蔀 佳奈子, 赤坂 司

  日本歯周病学会会誌 (NPO)日本歯周病学会 63 (秋季特別) 133 - 133 0385-0110 2021/10 [Not refereed]
  
• Ion Capture and Release Ability of Glass Ionomer Cement Containing Nanoporous Silica Particles with Different Pore and Particle Size

  R. Endo, K. Nakanishi, Y. Bando, S. Abe, H. Maruoka, M. Nakamura, T. Akasaka, Y. Yoshida, Y. Sato

  Materials 14 (19) 5742 - 5742 2021/10/01 [Refereed]
   

  This study prepared glass ionomer cement (GIC) containing nanoporous silica (NPS) (GIC–NPS) at 5 wt% concentrations using 3 types of NPS with different pore and particle sizes and evaluated the differences in their cationic ion capture/release abilities and mechanical properties. The cationic water-soluble dye was used as cationic ion. The test GIC–NPS complexes captured dyes by immersion in 1 wt% dye solutions. All the GIC–NPS complexes released dyes for 28 d, and the amount of dye released from the complexes increased with decreasing pore size; however, the particle size of NPS did not affect the amount of dye released. Additionally, GIC–NPS was able to recharge the dye, and the amount of released the dye by the complexes after recharge was almost identical to the amount released on the first charge. Although not significantly different, the compressive strength of GIC–NPS was slightly greater than that of GIC without NPS regardless of the type of NPS. These results suggest that the degree of capture and release of cationic molecules, such as drugs, can be controlled by optimizing the pore size of NPS without sacrificing its mechanical strength when its content is 5 wt%.
• Antibacterial and Antibiofilm Photodynamic Activities of Lysozyme-Au Nanoclusters/Rose Bengal Conjugates

  Ichie Okamoto, Hirofumi Miyaji, Saori Miyata, Kanako Shitomi, Tsutomu Sugaya, Natsumi Ushijima, Tsukasa Akasaka, Satoshi Enya, Satoshi Saita, Hideya Kawasaki

  ACS OMEGA 6 (13) 9279 - 9290 2470-1343 2021/04 [Refereed]
   

  Antibacterial photodynamic therapy (aPDT) utilizes reactive oxygen species such as singlet oxygen (O-1(2)) and free radicals via photosensitizers, which are light and light-sensitive agents, to reduce bacterial infections. It has been utilized as a treatment for dental diseases in place of antibiotic therapies. However, aPDT does not always cause the desired therapeutic effect due to the instability of organic photosensitizers and the formation of bacterial biofilms. To promote the antibacterial and antibiofilm effects of aPDT, we have proposed a lysozyme (Lys)-gold nanoclusters (Au NCs)/rose bengal (Lys-Au NCs/RB) conjugate as a novel photosensitizer. This conjugate was found to effectively impede the growth of both gram-positive and gram-negative bacteria when exposed to white light-emitting diode (LED) irradiation. The photoexcited Lys-Au NCs/RB showed significantly higher antibacterial activity than photoexcited Lys-Au NCs or RB alone. The synergistic effect is a result of the combination of Lys (an antibacterial protein) and enhanced O-1(2) generation related to resonance energy transfer (RET) in the Au NCs/RB conjugate. Photoexcited Lys-Au NCs/RB increased the effects of aPDT in a dose- and time-dependent manner. Furthermore, the photoexcited Lys-Au NCs/RB successfully decreased Streptococcus mutans biofilm formation. However, in contrast, it did not have a negative effect on the proliferation, adhesion, or spread of mammalian cells, indicating low cytotoxicity. Lys-Au NCs/RB is a novel photosensitizer with low cytotoxicity that is capable of bacterial inactivation and the suppression of biofilm formation, and could help to improve dental treatments in the future.
• Antibacterial coating of tooth surface with ion-releasing pre-reacted glass-ionomer (S-PRG) nanofillers

  Kayoko Mayumi, Hirofumi Miyaji, Saori Miyata, Erika Nishida, Tomokazu Furihata, Yukimi Kanemoto, Tsutomu Sugaya, Kanako Shitomi, Tsukasa Akasaka

  HELIYON 7 (2) 2405-8440 2021/02 [Refereed]
   

  Objectives: Surface pre-reacted glass-ionomer (S-PRG) fillers release antibacterial borate and fluoride ions. We fabricated nanoscale S-PRG fillers (S-PRG nanofillers) for antibacterial coating of tooth surfaces and assessed the antibacterial effects of this coating in vitro. In addition, we creating a canine model of periodontitis to evaluate the effectiveness of S-PRG nanofiller application on tooth roots and improvement of periodontal parameters.Methods: Human dentin blocks were coated with S-PRG nanofiller (average particle size: 0.48 mu m) and then characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX), and ion-releasing test. Antibacterial effects of dentin blocks coated with S-PRG nanofiller were examined using bacterial strains, Streptococcus mutans and Actinomyces naeslundii. Next, we created an experimental model of periodontitisin furcation of premolars of beagle dogs. Then, S-PRG nanofiller coating was applied onto exposed tooth root surfaces. Periodontal parameters, gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL), were measured from baseline until 4 weeks. In addition, bone healing was radiographically and histologically examined.Results: SEM and EDX revealed that S-PRG nanofillers uniformly covered the dentin surface after coating. Dentin blocks coated with S-PRG nanofiller showed ion-releasing property, bacterial growth inhibition, and sterilization effects. In the experimental periodontitis model, S-PRG nanofiller coating significantly reduced clinical inflammatory parameters, such as GI (P < 0.01) and BOP (P < 0.05), compared to uncoated samples. In addition, PPD and CAL significantly decreased by S-PRG nanofiller coating (2 weeks: P < 0.05; 3 and 4 weeks: P < 0.01), suggesting the improvement of periodontitis. Micro-CT and histology revealed that bone healing of furcation defects was enhanced by S-PRG nanofiller coating.Conclusion: S-PRG nanofiller coating provides antibacterial effects to tooth surfaces and improves clinical parameters of periodontitis.
• Evaluation of antibacterial and cytocompatible properties of multiple-ion releasing zinc-fluoride glass nanoparticles

  Erika Nishida, Hirofumi Miyaji, Kanako Shitomi, Tsutomu Sugaya, Tsukasa Akasaka

  DENTAL MATERIALS JOURNAL 40 (1) 157 - 164 0287-4547 2021/02 [Refereed]
   

  Zinc-fluoride glass nanoparticles (Zinc-F) release several ions, such as fluoride, zinc and calcium ions, through acid-base reactions. The aim of this study was to evaluate the antibacterial and cytotoxic properties of Zinc-F. Antibacterial tests showed that a Zinc-F eluting solution significantly reduced the turbidity and colony-forming units of Streptococcus mutans and Actinomyces naeslundii, compared to that of calcium-fluoroaluminosilicate glass nanoparticles without zinc ions. In live/dead staining, Zinc-F eluate significantly decreased green-stained bacterial cells, indicating live cells, compared with the control (no application). Human dentin coated with Zinc-F showed suppressed S. mutans and A. naeslundii biofilm formation. Additionally, Zinc-F eluate showed low cytotoxic effects in osteoblastic and fibroblastic cells. Therefore, our findings suggested that Zinc-F exhibits antibacterial and biocompatible properties through multiple-ion release.
• Bone forming ability of recombinant human collagen peptide granules applied with beta-tricalcium phosphate fine particles

  Tomokazu Furihata, Hirofumi Miyaji, Erika Nishida, Akihito Kato, Saori Miyata, Kanako Shitomi, Kayoko Mayumi, Yukimi Kanemoto, Tsutomu Sugaya, Tsukasa Akasaka

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS 108 (7) 3033 - 3044 1552-4973 2020/05 [Refereed][Not invited]
   

  Recombinant human collagen peptide, developed based on human collagen type I, contains an arginyl-glycyl-aspartic acid (RGD)-rich motif to enhance cell behavior and is anticipated as a xeno-free polymer material for use in tissue engineering. We fabricated granules containing recombinant human collagen peptide (RCP) applied with beta-tricalcium phosphate fine particles (RCP/beta-TCP) as bone filling scaffold material and assessed the bone forming ability of RCP/beta-TCP. Recombinant peptide was thermal crosslinked and freeze-dried to prepare RCP. An aqueous dispersion of beta-TCP fine particles was added to RCP to obtain RCP/beta-TCP. Subsequently, RCP/beta-TCP were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), and cell culture assessments. Furthermore, RCP/beta-TCP were implanted into rat cranial bone defects for radiographic and histological evaluations. In SEM and EDX analyses of RCP/beta-TCP, beta-TCP particles dose-dependently covered the surface of RCP. Cell culture tests showed that RCP/beta-TCP remarkably promoted proliferation and mRNA expression of various genes, such as integrin beta 1 and osteogenic markers, of osteoblastic MC3T3-E1 cells. Histomorphometric assessment at 4 weeks showed that RCP/beta-TCP significantly promoted new skull bone formation compared to RCP (p < 0.05) and control (no application) (p < 0.01). Accordingly, these findings suggest RCP/beta-TCP possess bone forming capability and would be beneficial for bone tissue engineering therapy.
• Size- and Morphology-Controlled Preparation of Surface-Modified Water-Dispersible Fullerene Nanoparticles for Bioapplications.

  Oguma H, Seitoku E, Mutoh M, Yoshizawa S, Nakanishi K, Bando Y, Era Y, Kiba T, Saikaew P, Tamai M, Akasaka T, Nakamura M, Kusaka T, Yoshida Y, Sato Y, Sano H, Abe S, Alireza V, Watanabe I, Inoue S, Takada T

  Journal of nanoscience and nanotechnology 20 (5) 2668 - 2674 1533-4880 2020/05 [Refereed][Not invited]
   

  In this study, we investigated water-dispersible surface modification for size- and shape-controlled fullerene nanoparticles (C₆₀P) based on a condensation reaction with di-amino alkane. This modification provided for water dispersibility of C₆₀P and the capability for secondary modification as well. The resultant C₆₀P particles have several useful physical properties: water-dispersibility for ease of injection; fluorescence for detection and quantification; and a characteristic morphology to assist identification. These properties will widely extend the applications of these particles, especially into the biological fields of bioimaging and drug delivery.
• Photodynamic inactivation of oral bacteria with silver nanoclusters/rose bengal nanocomposite.

  Kanako Shitomi, Hirofumi Miyaji, Saori Miyata, Tsutomu Sugaya, Natsumi Ushijima, Tsukasa Akasaka, Hideya Kawasaki

  Photodiagnosis and photodynamic therapy 30 101647 - 101647 1572-1000 2020/01/02 [Refereed][Not invited]
   

  Antibacterial photodynamic therapy (a-PDT) is a promising anti-infective technique for generation of singlet oxygen (1O2) to target dental disease. However, conventional organic photosensitizers have some problems for clinical use in terms of cytotoxicity, quenching of a-PDT activity by self-dimerization, and the lack of long-term antibacterial effect. We herein propose silver nanoclusters/rose bengal nanocomposite (AgNCs/RB) as a novel photosensitizer with two primary antibacterial effects: (1) 1O2 generation by irradiated RB and (2) Ag+ ion release from AgNCs. AgNCs/RB irradiated with white light-emitting diode (LED) for a short irradiation time of 1 min significantly decreased the bacterial turbidity of Streptococcus mutans, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans (P < 0.05). In SEM, TEM and LIVE/DEAD staining images, photoexcited AgNCs/RB reduced S. mutans colonization, destroyed the cell membrane, and increased the number of dead cells. The antibacterial efficiency of photoexcited AgNCs/RB was greater than that of AgNCs or RB alone (P < 0.05), suggesting a synergistic effect of 1O2 and Ag + ions from photoexcited AgNCs/RB. By contrast, photoexcited AgNCs/RB did not affect WST-8 and LDH activities and morphology of NIH3T3 mammalian cells, indicating low cytotoxicity. Interestingly, the antibacterial activity of AgNCs/RB on S. mutans was maintained even after the cessation of LED irradiation, indicating a long-term antibacterial effect due to released Ag+ ions. The present AgNCs/RB photosensitizers provide effective synergistic antibacterial effects for dental a-PDT via 1O2 and Ag+ ions coupled with low cytotoxicity.
• Morphology and fluorescence of Y2O3:Eu³⁺ nanophosphors and dispersibility in adhesives resins

  Shuichi Yamagata, Takaaki Yamamoto, Yoshiaki Sato, Natsumi Ushijima, Tsukasa Akasaka, Yasuhiro Yoshida

  Nano Biomedicine 11 (2) 57 - 64 1883-5198 2020 [Refereed]
   

  After orthodontic treatment has been completed, we consider fluorescent imaging to be one of the most effective solutions for secure removal of colorless residual adhesives from tooth surfaces using cutting instruments. Nanoscale Y2O3:Eu3+ particles were synthesized using the homogeneous precipitation method with two different starting concentrations of urea aqueous solutions, followed by firing at 1000°C. These particles exhibited narrow size distribution (approx. 200–300 nm) and sharp crystallinity regardless of the urea concentration. Moreover, their photoluminescence peak corresponded well with the typical 4f-4f transitions of Eu3+. The Y2O3:Eu3+ particles were almost uniformly dispersed and retained in the monomer blends and polymerized bulk bodies. Photoluminescence measurement is a valid detection method and can be useful for future studies on dispersion control. We conclude that the crystalline Y2O3:Eu3+ particles could be applicable for further development of fluorescent orthodontic adhesives.
• Fluorescence mechanical properties of Y2O3:Eu³⁺ and Nanophosphor-containing adhesive resins

  Shuichi Yamagata, Takaaki Yamamoto, Yoshiaki Sato, Natsumi Ushijima, Tsukasa Akasaka, Yasuhiro Yoshida

  Nano Biomedicine 12 (1) 19 - 26 1883-5198 2020 [Refereed]
   

  Secure removal of remnants on tooth surfaces by rotary cutting instruments after an orthodontic treatment could be guaranteed if the orthodontic adhesive used is highly visible. Fluorescent imaging is a potentially effective solution for increasing the visibility of orthodontic adhesives. In this study, Y2O3:Eu3+ nanoparticles were synthesized by a homogeneous precipitation method followed by firing at 1,000 °C. The size of most of the synthesized nanoparticles was approximately 200 nm in diameter. The photoluminescence properties of the nanoparticles were similar to that of the typical 4f-4f transition of Eu3+. Regardless of the concentration of the particle, the nanoparticles were almost uniformly dispersed and remained in their polymerized bodies without deteriorating the intrinsic flexural modulus of the dimethacrylate resin. Although the fluorescence of the 10 wt%-phosphor-containing resins was adequately recognizable to the naked eye, it was suggested that the preferred concentration of Y2O3:Eu3+ nanoparticles should be more than 10 wt% in terms of fluorescence intensity.
• Proliferation of Saos-2 and Ca9-22 cells on grooved and pillared titanium surfaces.

  Kaga N, Akasaka T, Matsuura T, Yokoyama A, Yoshida Y

  Bio-medical materials and engineering 30 (5-6) 559 - 567 0959-2989 2020/01 [Refereed][Not invited]
   

  BACKGROUND: Surface nanostructures in titanium (Ti) oral implants are critical for rapid osseointegration.OBJECTIVE: The purpose of this study was to evaluate the growth of osteoblast-like (Saos-2) and epithelial-like (Ca9-22) cells on nanopatterned Ti films.METHODS: Ti films with 500 nm grooves and pillars were fabricated by nanoimprinting, and seeded with Saos-2 and Ca9-22 cells. Cell viability and morphology were assessed by cell proliferation assay and scanning electron microscopy, respectively.RESULTS: As assessed after 1 hour, proliferation of Saos-2 cells was most robust on grooved films than on pillared and smooth films, in this order. These cells approximately doubled on grooved and pillared substrates in 24 hours and after 5 days, but not on smooth surfaces. In contrast, Ca9-22 cells favored smooth surfaces, followed by grooved and pillared films. Indeed, cells sparsely adhered to pillared films over 5 days of incubation (p < 0.05).CONCLUSIONS: The data show that Saos-2 and Ca9-22 cells respond differently to different nanostructures, and highlight the potential use of nanopatterns to promote bone regeneration or to prevent epithelial downgrowth at the implant-bone interface.
• Comparative biological assessments of endodontic root canal sealer containing surface pre-reacted glass-ionomer (S-PRG) filler or silica filler.

  Hirofumi Miyaji, Kayoko Mayumi, Saori Miyata, Erika Nishida, Kanako Shitomi, Asako Hamamoto, Saori Tanaka, Tsukasa Akasaka

  Dental materials journal 39 (2) 287 - 294 0287-4547 2019/11/28 [Refereed][Not invited]
   

  Surface pre-reacted glass-ionomer (S-PRG) filler releases several ions, such as fluoride, borate and strontium ions, to exert bioactive effects. We fabricated an endodontic root canal sealer containing S-PRG fillers (S-PRG sealer) and then evaluated the antibacterial and anti-inflammatory properties of S-PRG sealer compared with sealer containing conventional silica fillers (silica sealer). Antibacterial tests showed that S-PRG sealer significantly reduced the turbidity of Enterococcus faecalis compared with silica sealer. Implantation of S-PRG or silica sealer blocks in rat subcutaneous tissue showed that S-PRG sealer decreased the proinflammatory response compared with silica sealer at 10 days post-implantation. In addition, immunostaining revealed that infiltration of CD68- and peroxidase-positive cells around the S-PRG sealer was significantly lower than that in silica sealer. Therefore, it was suggested that S-PRG sealer exhibits antibacterial and anti-inflammatory effects.
• Fusion of RAW 264.7 macrophage cells on micro-scale fine pillar patterns

  J. Honma, T. Akasaka, M. Tamai, Y. Yoshimura, T. Taira, H. Miyaji, S. Yamagata, Y. Sato, Y. Yoshida

  Digest Journal of Nanomaterials and Biostructures 13 (4) 1123 - 1131 2018/12 [Refereed][Not invited]
  
• Optical and Chromatic Evaluation of Fluorescent Orthodontic Bonding Materials Doped with a Europium β-diketonate Complex

  Aiko MATSUMOTO, Shuichi YAMAGATA, Shigeaki ABE, Tsukasa AKASAKA, Yasuhiro YOSHIDA, Junichiro IIDA

  Nano Biomedicine 10 (1) 3 - 8 2018/08 [Refereed][Not invited]
  
• Evaluation of Tissue Behavior on Three-dimensional Collagen Scaffold Coated with Carbon Nanotubes and β-tricalcium Phosphate Nanoparticles

  Hirofumi MIYAJI, Shusuke MURAKAMI, Erika NISHIDA, Tsukasa AKASAKA, Bunshi FUGETSU, Junko UMEDA, Katsuyoshi KONDOH, Tadashi IIZUKA, Tsutomu SUGAYA

  Journal of Oral Tissue Engineering 15 (3) 123 - 130 2018/05 [Refereed][Not invited]
  
• Effect of a nano-scale fine hole pattern on the differentiation of RAW264.7 Cells into osteoclasts

  R. Takata, T. Akasaka, M. Tamai, Y. Yoshimura, T. Taira, H. Miyaji, Y. Tagawa, S. Yamagata, J. Iida, Y. Yoshida

  Digest Journal of Nanomaterials and Biostructures 13 (2) 451 - 458 2018/04 [Refereed][Not invited]
  
• Near-infrared Irradiation and Graphene Oxide Film Fabricated on Dentin Surface Exhibit Photothermal and Antibacterial Effects

  Nagao Keishi, Miyaji Hirofumi, Nishida Erika, Akasaka Tsukasa, Miyata Saori, Shitomi Kanako, Mayumi Kayoko, Kato Akihito, Sugaya Tsutomu

  Journal of Oral Hygiene & Health OMICS International 6 (1) 231 - 231 2018/01/10 [Refereed][Not invited]
  
• Fabrication of light-curing type fluorescent orthodontic bonding materials using europium-ß-diketonate complex

  Shuichi Yamagata, Takaaki Yamamoto, Yoshiaki Sato, Shigeaki Abe, Tsukasa Akasaka, Yasuhiro Yoshida

  Nano Biomedicine 10 (2) 53 - 60 1883-5198 2018 [Refereed]
   

  We successfully prepared light-curing type fluorescent resins as orthodontic adhesives doped with tris(1,3-diphenyl-1,3-propanedionato)(1,10-phenanthroline)Eu(III) [Eu(DBM)3Phen] by a photoinduced radical polymerization method. The transparent and almost colorless appearance of the composites under natural light is favorable for an esthetic dental product. The strong luminescence under near-UV light, especially when the content of Eu(DBM)3 Phen is above 0.1 wt%, is promising for safe and complete removal of this adhesive after completing orthodontic treatments. We have also found that concentration quenching may occur around a concentration of 0.2-0.4 wt%. Based on the results obtained, in situ monomer polymerization can be applicable to Eu(DBM)3Phen-containing adhesives. Although we are still investigating this proposed system, we conclude that the Eu(DBM)3Phen-containing adhesives is a promising candidate for application to fluorescent orthodontic adhesives.
• Y2O3:Eu3+ phosphors by homogeneous precipitation and subsequent calcination at varied temperatures for orthodontic adhesives

  Shuichi Yamagata, Takaaki Yamamoto, Yoshiaki Sato, Natsumi Ushijima, Shigeaki Abe, Tsukasa Akasaka, Yasuhiro Yoshida, Junichiro Iida

  Nano Biomedicine 9 (1) 15 - 22 2185-4734 2018 [Refereed][Not invited]
   

  Subsequent to the orthodontic treatment, removal of residual colorless adhesives from tooth surfaces by cutting instruments with the lowest possible iatrogenic damage has been a long-standing challenge. Fluorescent imaging can be one of the most effective solutions. Y2O3:Eu3+ particles were synthesized by a homogeneous precipitation method and the subsequent calcination was performed at various temperatures. The particles had a narrow size distribution (200-300 nm) and showed sharp crystallinity independent of the calcination temperatures above 800 °C. In this study, 1,000 °C is confirmed to be the optimum calcination temperature. Although the reason for the decline in emission intensity of the 1,100 °C-calcined particles is still unclear, loss of spherical shape associated with excessive crystal grain growth and simultaneous sintering to each other by firing is a possible explanation. The emission from the phosphor-containing resins, intended for use in orthodontic adhesives, is appreciable although the emission intensity of the resins was weak even if their content was 20 wt.%. The decrease in emission intensity may be attributed to the scattering by the particles or cross relaxation processes. We conclude that the crystalline Y2O3:Eu3+ particles calcined at 1,000 °C could be applicable for further development of photoluminescent orthodontic adhesives.
• Preparation of micro/nanopatterned gelatins crosslinked with genipin for biocompatible dental implants.

  Reika Makita, Tsukasa Akasaka, Seiichi Tamagawa, Yasuhiro Yoshida, Saori Miyata, Hirofumi Miyaji, Tsutomu Sugaya

  Beilstein journal of nanotechnology 9 1735 - 1754 2018 [Refereed][Not invited]
   

  Background: Collagen is a basic component of the periodontium and plays an important role in the function of the periodontal unit. Therefore, coating with collagen/gelatin has been applied to enable dental implants to positively interact with peri-implant tissues. Although the micro/nanoscale topography is an important property of the surface of dental implants, smaller collagen/gelatin surface patterns have not been sufficiently developed. Furthermore, only few reports on the behavior of cells on gelatin surfaces with different patterns and sizes exist. In this study, we developed micro/nanometer-scaled gelatin surfaces using genipin crosslinking, with the aim of understanding the use of patterning in surface modification of dental implants. Results: Grooves, holes, and pillars, with widths or diameters of 2 µm, 1 µm, or 500 nm were fabricated using a combination of molding and genipin crosslinking of gelatin. The stability of the different gelatin patterns could be controlled by the degree of genipin crosslinking. The gelatin patterns at 20 mM concentration of genipin and 41% crosslinking maintained a stable, patterned shape for at least 14 days in a cell culture medium. A cell morphology study showed that the cells on groves were aligned along the direction of the grooves. In contrast, the cells on pillars and holes exhibited randomly elongated filopodia. The vinculin spots of the cells were observed on the top of ridges and pillars or the upper surface of holes. The results of a cell attachment assay showed that the number of surface-attached cells increased with increasing patterning of the gelatin surface. Unlike the cell attachment assay, the results of a cell proliferation assay showed that Saos-2 cells prefer grooves with diameters of approximately 2 µm and 1 µm and pillars with diameters of 1 µm and heights of 500 nm. The number of cells on pillars with heights of 2 µm was larger than those of the other gelatin surface patterns tested. Conclusion: These data support that a detailed design of the gelatin surface pattern can control both cell attachment and proliferation of Saos-2 cells. Thus, gelatin surfaces patterned using genipin crosslinking are now an available option for biocompatible material patterning.
• Dose effects of beta-tricalcium phosphate nanoparticles on biocompatibility and bone conductive ability of three-dimensional collagen scaffolds.

  Shusuke Murakami, Hirofumi Miyaji, Erika Nishida, Kohei Kawamoto, Saori Miyata, Hiroko Takita, Tsukasa Akasaka, Bunshi Fugetsu, Toshihiko Iwanaga, Hiromi Hongo, Norio Amizuka, Tsutomu Sugaya, Masamitsu Kawanami

  Dental materials journal 36 (5) 573 - 583 2017/09/26 [Refereed][Not invited]
   

  Three-dimensional collagen scaffolds coated with beta-tricalcium phosphate (β-TCP) nanoparticles reportedly exhibit good bioactivity and biodegradability. Dose effects of β-TCP nanoparticles on biocompatibility and bone forming ability were then examined. Collagen scaffold was applied with 1, 5, 10, and 25 wt% β-TCP nanoparticle dispersion and designated TCP1, TCP5, TCP10, and TCP25, respectively. Compressive strength, calcium ion release and enzyme resistance of scaffolds with β-TCP nanoparticles applied increased with β-TCP dose. TCP5 showed excellent cell-ingrowth behavior in rat subcutaneous tissue. When TCP10 was applied, osteoblastic cell proliferation and rat cranial bone augmentation were greater than for any other scaffold. The bone area of TCP10 was 7.7-fold greater than that of non-treated scaffold. In contrast, TCP25 consistently exhibited adverse biological effects. These results suggest that the application dose of β-TCP nanoparticles affects the scaffold bioproperties; consequently, the bone conductive ability of TCP10 was remarkable.
• Antibacterial and cytotoxic effects of photoexcited Au clusters via blue high-power or white low-power light emitting diode irradiation

  Saori Miyata, Hirofumi Miyaji, Hideya Kawasaki, Erika Nishida, Kanako Shitomi, Tsukasa Akasaka, Saori Tanaka, Tadashi Iizuka, Tsutomu Sugaya

  Biology, Engineering and Medicine Open Access Text 2 (4) 1 - 4 2399-9632 2017/09 [Refereed][Not invited]
   

  The development of photosensitizers and light sources has enabled the use of antimicrobial photodynamic therapy (aPDT) in various dental therapies. In the presentstudy, we compared the antibacterial and cytotoxic effects of Au clusters photoexcited by blue and white LED irradiation. We fabricated novel photosensitizers,captopril-protected gold (Capt-Au) clusters and lysozyme-stabilized gold (Lyz-Au) clusters, for aPDT. Au clusters were then photoexcited by two kinds of lightsources, blue high-power and white low-power light-emitting diodes (LEDs). Since white LED contains a wide spectrum of light (400–750 nm), white LED wouldbe relevant for aPDT even if using a low-power source.The turbidity and viability of Streptococcus mutans were assessed following application of Capt-Au clusters (500 μg/mL) or Lyz-Au clusters (1,000 μg/mL) photoexcitedby a blue high-power LED (1,000 mW/cm2) or white low-power LED (80 mW/cm2). In addition, the cytotoxicity of Au clusters and LED irradiation was evaluatedin NIH3T3 and MC3T3-E1 cells.Au clusters photoexcited by the white low-power LED equally decreased the turbidity and viability of S. mutans compared with blue high-power LED. However,Au clusters photoexcited by white LED irradiation caused decreased cytotoxicity in mammalian cells compared with those photoexcited by blue LED irradiation. Inconclusion, white LEDs possess biosafe properties for aPDT using Au clusters.
• Interfacial interactions of bioadhesive materials with human hard tissues

  Yoshida, Yasuhiro, Inoue, Satoshi, Tamai, Miho, Abe, Shigeaki, Akasaka, Tsukasa, Yoshihara, Kumiko, Meerbeek, Bart Van

  Hokkaido Journal of Dental Science 北海道歯学会 38 86 - 98 0914-7063 2017/09 [Refereed][Not invited]
   

  Recently, in dental practice, tooth reconstruction can be performed using dental adhesive technology following either a "glass-ionomer", an "etch-and-rinse" or a "self-etch" approach. Glass-ionomer cements are well-known to possess an auto-adhesive capability without requiring any surface pre-treatment. The fundamental bonding mechanism of resin-based materials to enamel and dentin is essentially based on an exchange process, in which minerals removed from the dental hard tissues are replaced by resin monomers. These resin monomers, upon polymerization become micro-mechanically interlocked in the created porosities. Besides micro-mechanical interlocking through hybridization, an additional chemical interaction between functional monomers/polymers and tooth substrate components has been found to be important. In this review, we focus on how the chemical interaction of the biomaterial-hard tissue interface can improve bond durability, especially using chemical analytical techniques.
• Cell adhesion and alignment of human osteoblasts and human gingival fibroblasts on micro/nano-grooved gelatin sheet

  Naoyuki Kaga, Tsukasa Akasaka, Rumi Horiuchi, Yasuhiro Yoshida, Atsuro Yokoyama

  Digest Journal of Nanomaterials and Biostructures 12 (2) 431 - 440 2017/05 [Refereed][Not invited]
  
• SUBMICRO-PATTERNING OF CURABLE DENTAL MATERIALS BY MOLDING METHODS: A SCREENING TRIAL

  T. Akasaka, H. Miyaji, T. Imamura, N. Kaga, A. Yokoyama, Y. Yoshida

  DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES 12 (2) 281 - 292 1842-3582 2017/04 [Refereed][Not invited]
   

  We investigated patterning with curable dental materials via micro/nano-molding as a screening trial. We used typical curable dental materials such as a composite resin (CR), acrylic resin, varnish, adhesive resin, restoration, sealer, cement, tooth desensitizer, and gypsum with either a cyclo-olefin polymer (COP) mold or polydimethylsiloxane (PDMS) mold that had holes, pillars, and grooves with 0.5 mu m diameters and 1 mu m heights. The COP mold was suitable for patterning of holes and grooves with Bondfill SB after 2 h curing, while PDMS mold was suitable for patterning of pillars with Bondfill SB at the 0.5 mu m scale after 2 h curing. Most of the curable dental materials could be patterned using the COP or the PDMS mold. However, dental impression materials could not be patterned as required. In addition, the COP mold was suitable for many organic pillars, while the PDMS mold was suitable for inorganic pillars. Further, we achieved patterning on the curved surface of an artificial tooth with flowable CR using the COP thin film mold. We conclude that for the formation of uniform shaped patterns, it is important to cure within a suitable time and to select mold types depending on the type of curable dental material.
• Effect of micro/nano-patterned surfaces on cell adhesion of Ca9-22 cells

  Naoyuki Kaga, Rumi Horiuchi, Atsuro Yokoyama, Tsukasa Akasaka, Yasuhiro Yoshida

  e-Journal of Surface Science and Nanotechnology 15 1 - 6 1348-0391 2017/02/11 [Refereed][Not invited]
   

  Surface topography influences cell growth and differentiation. In this study, we used a nano-imprinting method to develop a titanium sheet with 500 nm-, 1 μm-, and 2 μm-wide grooved and pillared structures. We investigated the effects of the surfaces with the micro- and nano-structures on Ca9-22 cell adhesion and proliferation. Ca9-22 cells were cultured in DMEM containing 10% fetal bovine serum and counted adhered cells at 1 and 24 h post-culture. Scanning electron microscopy was used to assess cell morphology. Immunofluorescence cell staining was used to evaluate vinculin formation to observe the presence of focal contacts at 24 h. There was no difference in cell adhesion between cells cultured on a plane or groove after 1 h. However, at 24 h, the adhesion of cells cultured on the groove was reduced. In addition, the cell adhesion count on the pillar was less than that of cells cultured on a plane at both 1 hour and 24 h post-seeding. Furthermore, in the groove of the Ti sheet after 1 and 24 h, cell expansion occurred in the grooved direction. These results demonstrate that the micro and nano-grooved and pillared structures on the titanium sheet control Ca9-22 cell adhesion and orientation.
• Antimicrobial photodynamic activity and cytocompatibility of Au25(Capt)18 clusters photoexcited by blue LED light irradiation.

  Saori Miyata, Hirofumi Miyaji, Hideya Kawasaki, Masaki Yamamoto, Erika Nishida, Hiroko Takita, Tsukasa Akasaka, Natsumi Ushijima, Toshihiko Iwanaga, Tsutomu Sugaya

  International journal of nanomedicine 12 2703 - 2716 2017 [Refereed][Not invited]
   

  Antimicrobial photodynamic therapy (aPDT) has beneficial effects in dental treatment. We applied captopril-protected gold (Au25(Capt)18) clusters as a novel photosensitizer for aPDT. Photoexcited Au clusters under light irradiation generated singlet oxygen (1O2). Accordingly, the antimicrobial and cytotoxic effects of Au25(Capt)18 clusters under dental blue light-emitting diode (LED) irradiation were evaluated. 1O2 generation of Au25(Capt)18 clusters under blue LED irradiation (420-460 nm) was detected by a methotrexate (MTX) probe. The antimicrobial effects of photoexcited Au clusters (0, 5, 50, and 500 μg/mL) on oral bacterial cells, such as Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis, were assessed by morphological observations and bacterial growth experiments. Cytotoxicity testing of Au clusters and blue LED irradiation was then performed against NIH3T3 and MC3T3-E1 cells. In addition, the biological performance of Au clusters (500 μg/mL) was compared to an organic dye photosensitizer, methylene blue (MB; 10 and 100 μg/mL). We confirmed the 1O2 generation ability of Au25(Capt)18 clusters through the fluorescence spectra of oxidized MTX. Successful application of photoexcited Au clusters to aPDT was demonstrated by dose-dependent decreases in the turbidity of oral bacterial cells. Morphological observation revealed that application of Au clusters stimulated destruction of bacterial cell walls and inhibited biofilm formation. Aggregation of Au clusters around bacterial cells was fluorescently observed. However, photoexcited Au clusters did not negatively affect the adhesion, spreading, and proliferation of mammalian cells, particularly at lower doses. In addition, application of Au clusters demonstrated significantly better cytocompatibility compared to MB. We found that a combination of Au25(Capt)18 clusters and blue LED irradiation exhibited good antimicrobial effects through 1O2 generation and biosafe characteristics, which is desirable for aPDT in dentistry.
• Effect of protein adsorption on alignment of human gingival fibroblasts on grooved composite resin

  Tsukasa Akasaka, Takuya Imamura, Hirofumi Miyaji, Naoyuki Kaga, Atsuro Yokoyama, Yasuhiro Yoshida

  e-Journal of Surface Science and Nanotechnology 14 225 - 230 1348-0391 2016/12/10 [Refereed][Not invited]
   

  Groove patterns on the surface of implants act as an effective barrier to the apical migration of epithelial attachment, after which the grooves facilitate gingival fibroblast attachment. Cell alignment on grooves is largely influenced by the adsorbed protein type. However, cell attachment and cell alignment properties of micro/nanogrooved dental composite resins using osteoblasts and fibroblasts have not been investigated. Further, the effect of saliva-related protein adsorption has not investigated. In this study, we prepared composite resins with grooves that were 2 μm, 1 μm, and 500 nm wide and estimated the effect of pre-coating of some proteins, mainly mucin, on attachment and alignment of human gingival fibroblasts(HGF). In the cell attachment assay on mucin-coated grooves, the number of attached cells on mucin-coated planar or grooved composite resins was lower compared to that on both composite resins without pre-coating of mucin. Interestingly, the number of attached cells on grooves pre-coated with mucin was 5.7-fold higher than those on planar pre-coated with mucin. Grooves at the micro/nano level may act as a hook for floating cells during the cell attachment assay. Furthermore, the degree of cell alignment was strongly dependent on the pre-coating protein types. The cells were radially spread or round-shaped, but not have sufficient alignment on non-, mucin-, and albumin-coated grooves. Although the cells were attached on the grooves, they were not aligned along the direction of grooves. The cells on fetal bovine serum- or fibronectin-coated grooves exhibited good alignment in the groove direction, particularly on fibronectin-coated grooves. Thus, our patterning method creates an effective seal between soft tissue and dental materials to protect against microorganism invasion.
• Adhesion of human osteoblast-like cells (Saos-2 cells) on micro/nanopatterned structures sputter-coated with titanium

  Kaga N, Akasaka T, Horiuchi R, Yoshida Y, Yokoyama A

  Nano Biomedicine 8 (2) 74 - 82 2016/12 [Refereed][Not invited]
  
• Adhesion of osteoblast-like cells (Saos-2) on micro-/submicro-patterned apatite scaffolds fabricated with apatite cement paste by micro-molding

  Akasaka T, Miyaji H, Kaga N, Yokoyama A, Abe A, Yoshida Y

  Nano Biomedicine 8 (2) 112 - 122 2016/12 [Refereed][Not invited]
  
• Evaluation of Fluorescent Orthodontic Adhesives Containing Y2O3:Eu3+ Particles

  Shuichi YAMAGATA, Yoshiaki SATO, Takaaki YAMAMOTO, Shigeaki ABE, Tsukasa AKASAKA, Yasuhiro YOSHIDA, Junichiro IIDA

  Nano Biomedicine 8 (1) 35 - 40 1883-5198 2016/10 [Refereed][Not invited]
   

  Orthodontic adhesives are usually colorless and transparent for aesthetic purposes. However, making such adhesives fluorescent is one of the most effective solutions to make them visible to ensure safe and complete removal after orthodontic treatments. Trivalent europium ions were doped into yttrium oxides by a homogeneous precipitation method. The particles were synthesized via a homogeneous precipitation method and had a narrow size distribution (200-300 nm) and showed sharp crystallinity independent of the starting concentration of Eu3+. The strongest emission and absorption peaks were identified at 611 nm and 396 nm, respectively. In this study, 8 mol% was confirmed to be the optimum doping concentration. The emission intensity of phosphor containing PMMA adhesives was appreciably weak even when the concentration of phosphors was 10 wt%. It may be attributed to the clustering of the particles or a multiphonon relaxation process owing to organic groups in the polymer. We conclude that the crystalline Y2O3:Eu3+ particles could be applicable for the development of fluorescent orthodontic adhesives.
• Evaluation of a Gliding Arc Discharge Non-thermal Atmospheric Pressure Plasma Device for Orthodontic Bonding

  Shuichi YAMAGATA, Takaaki YAMAMOTO, Yoshiaki SATO, Shigeaki ABE, Tsukasa AKASAKA, Yasuhiro YOSHIDA, Junichiro IIDA

  Nano Biomedicine 8 (1) 57 - 63 1883-5198 2016/10 [Refereed][Not invited]
   

  The purpose of this study was to investigate the effect of gliding arc discharge non-thermal atmospheric pressure plasma with N2 carrier gas on surface chemical modification for adhesion improvement. The shear bond strength between the orthodontic adhesive resin and plasma-treated stainless steel surface improved slightly, although the surface free energy of the stainless steel samples increased from 73.6 mJm-2 to 112.9 mJm-2 mainly due to an increase of the dipole component (γSp) and partially due to an increase of the hydrogen bond component (γSh). This is partly because the metastability of the stainless steel surface was stabilized by immediate hydration or adsorption of water on the highly hydroxylated stainless steel surfaces. However, surface cleaning and hydroxylating efficacy of the handheld device was determined to be superior to those of other surface cleaning procedures, particularly in terms of intraoral applications. The technique may be potentially employed in establishing M-S coordinate bonds in dental precious metals and related alloys.
• Development of Poly(L-lactic acid)/Organically Modified Montmorillonite Nanocomposites for the Fabrication of Orthodontic Anchoring Screws

  Ko Nakanishi, Shuichi Yamagata, Tsukasa Akasaka, Shigeaki Abe, Yasuhiro Yoshida, Junichiro Iida

  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 16 (9) 9292 - 9297 1533-4880 2016/09 [Refereed][Not invited]
   

  Titanium orthodontic anchoring screws are being increasingly used as a source of orthodontic force. However, the incidence of screw fracture during insertion and removal is not negligible; sometimes, invasive procedures are required for removal of the screw fragments. Therefore, poly(L-lactic acid) (PLLA)/organically modified montmorillonite (OMMT) nanocomposites were fabricated via a solution intercalation method for the development of novel orthodontic anchoring screws with adequate mechanical strength and bioabsorbability. The structural features and mechanical and thermal properties of the screws were characterized, and the viability of cells exposed to OMMT was also investigated to evaluate the biological safety of the PLLA/OMMT composites. Human osteosarcoma (MG-63) and mouse osteoblastic (MC3T3-E1) cell lines were used as target cells. The (001) diffraction peaks in the X-ray diffraction patterns of samples of pure OMMT, and polymer composites containing 2 and 4 vvt% OMMT were 2 theta = 2.5, 2.3, and 2.3 degrees, indicating interlayer distances of 3.5, 3.8 and 3.8 nm, respectively. Transmission electron microscopy images of the nanocomposite with 4 wt% OMMT revealed that the interlayer distance of the compounded OMMT was irregularly enlarged and ranged from 2 to 5 nm. In addition, some of OMMT layers were exfoliated. The flexural modulus values of the nanocomposites were significantly increased compared to that for pure PLLA, according to the results of three-point transverse analyses. Differential scanning calorimetry measurements also revealed that the glass transition temperatures, melting temperatures and degree of crystallinity were nearly the same for all of the samples and, thus, independent of the quantity of added OMMT. The cell viabilities for the MG-63 and MC3T3-E1 cells (greater than 90% and 80%, respectively) were also independent of the OMMT concentration. Scanning electron microscopy images of both types of cells following OMMT exposure exhibited normal shapes. Based on these results, we conclude that PLLA/OMMT nanocomposites prepared via solution intercalation should be useful for the development of bioabsorbable orthodontic anchoring screws.
• Estimation of Biocompatibility of Nano-Sized Ceramic Particles with Osteoblasts, Osteosarcomas and Hepatocytes by Static and Time-Lapse Observation

  Shigeaki Abe, Eri Seitoku, Nobuki Lwadera, Yusuke Hamba, Shuichi Yamagata, Tsukasa Akasaka, Teruo Kusaka, Satoshi Lnoue, Yasutaka Yawaka, Junichiro Lida, Hidehiko Sano, Tetsu Yonezawa, Yasuhiro Yoshida

  JOURNAL OF BIOMEDICAL NANOTECHNOLOGY 12 (3) 472 - 480 1550-7033 2016/03 [Refereed][Not invited]
   

  We assessed the biocompatibility of nano-sized ceramic particles with several cells types. Though these particles have less than 100 nm in diameter, they act as submicron-sized particles in saline by aggregation that was estimated using laser diffraction particle size analysis (LDS). they act as submicro-sized particles in saline by aggregation based on laser diffraction particle size analysis (LDS). Several types of cells (osteoblasts, osteosarcoma and hepatocyte cells) were exposed to these particles and their cytocompatibility was estimated. Not only the cytotoxic assay but also their static and dynamic morphology under nanoparticles exposure were investigated. The intercellular uptake of particles was determined using a confocal fluorescence microscope. The particles used in this study did not inhibit cellular activity or growth even when their concentrations were high. Only copper oxide particles caused acute cytotoxicity depending on the particle size. The cytotoxicity assay, dynamic behavior of the nanoparticle-exposed cells and their examination under a confocal fluorescence microscope suggests that the irritative reaction was induced by contact between the cells and particles, whereas eluted copper ions are not dominant factor. These results indicate that nano-sized particles used in this study have excellent biocompatibility except copper oxide ones.
• Cytocompatiblity of ceramic nano particles to various types of cells

  Shigeaki Abe, Nobuki Iwadera, Mami Mutoh, Tomohiko Katsurayama, Shino Morimoto, Ko Nakanishi, Tsukasa Akasaka, Satoshi Inoue, Yasutaka Yawaka, Junichiro Iida, Yasuhiko Yoshida

  Key Engineering Materials 696 234 - 237 1013-9826 2016 [Refereed][Not invited]
   

  In this study, we investigated the cytocompatibility of ceramic nanoparticles on different types of cells. All ceramics nanoparticles investigated in this study except Copper oxide (CuO) exhibited good cytocompatibility and cell viability (90% or more) even at 20 ppm concentration. In contrast, CuO nanoparticles caused cell inflammation, and their effect depended on their particle size. Confocal fluorescence microscopy measurements indicated that some particles had penetrated into the cells. These results indicate that except CuO nanoparticles, all other ceramic nanoparticles reported herein exhibited excellent cytocompatibility even for lung epithelial cells.
• Biological Response to Nanostructure of Carbon Nanotube/titanium Composite Surfaces

  Erika NISHIDA, Hirofumi MIYAJI, Junko UMEDA, Katsuyoshi KONDOH, Hiroko TAKITA, Izumi KANAYAMA, Saori TANAKA, Akihito KATO, Bunshi FUGETSU, Tsukasa AKASAKA, Masamitsu KAWANAMI

  Nano Biomedicine 7 (1) 11 - 20 2015/06 [Refereed][Not invited]
  
• Preparation of a poly(lactic acid)/montmorillonite nanocomposite

  NAKANISHI KO, YAMAGATA SHUICHI, AKASAKA TSUKASA, ABE SHIGEAKI, YOSHIDA YASUHIRO, IIDA JUNICHIRO

  Key Eng Mater 631 151 - 155 1013-9826 2015 [Not refereed][Not invited]
  
• Platinum on Nanodiamond: A Promising Prodrug Conjugated with Stealth Polyglycerol, Targeting Peptide and Acid-Responsive Antitumor Drug

  Li Zhao, Yong-Hong Xu, Hongmei Qin, Shigeaki Abe, Tsukasa Akasaka, Tokuhiro Chano, Fumio Watari, Takahide Kimura, Naoki Komatsu, Xiao Chen

  ADVANCED FUNCTIONAL MATERIALS 24 (34) 5348 - 5357 1616-301X 2014/09 [Refereed][Not invited]
   

  In the field of nanomedicine, nanoparticles with various functions are required for in vivo applications such as biomedical imaging and drug delivery. Therefore, chemical functionalization of nanoparticles has been extensively investigated. Herein, nanodiamond (ND) coated with polyglycerol (PG) and its derivatives is reported to impart good solubility in a physiological environment, a stealth nature to avoid nonspecific uptake, a targeting property to be taken up by a specific cell, and an acid-responsive drug release property to kill cancer cells. ND is first grafted with PG and the resulting ND-PG has a high solubility in physiological media. Since a large number of hydroxyl groups in PG provide scaffolds for further surface functionalization, the targeting RGD peptide and Pt-based drug are immobilized to give ND-PG-RGD, ND-PG-Pt and ND-PG-RGD-Pt. The ND with intrinsic fluorescence is also functionalized by PG and RGD to confirm cellular uptake and intracellular localization fluorescently. The results of the cell experiments indicate that PG coating shielded fND from the uptake by HeLa and U87MG cells. In contrast, fND-PG-RGD is taken up by U87MG, not HeLa cells, exhibiting high targeting efficacy. When ND-PG-RGD-Pt is applied, U87MG is selectively killed against HeLa. The multi-functional ND is a promising prodrug in targeting chemotherapy.
• Polyglycerol-coated nanodiamond as a macrophage-evading platform for selective drug delivery in cancer cells

  Li Zhao, Yong-Hong Xu, Tsukasa Akasaka, Shigeaki Abe, Naoki Komatsu, Fumio Watari, Xiao Chen

  BIOMATERIALS 35 (20) 5393 - 5406 0142-9612 2014/07 [Refereed][Not invited]
   

  A successful targeted drug delivery device for cancer chemotherapy should ideally be able to avoid nonspecific uptake by nonmalignant cells, particularly the scavenging monocyte-macrophage system as well as targeting efficacy to bring the drug preferentially into tumor cells. To this purpose, we developed a platform based on detonation nanodiamond (dND) with hyperbranched polyglycerol (PG) coating (dND-PG). dND-PG was first demonstrated to evade non-specific cell uptake, particularly by macrophages (U937). RGD targeting peptide was then conjugated to dND-PG through multistep organic transformations to yield dND-PG-RGD that still evaded macrophage uptake but was preferentially taken up by targeted A549 cancer cells (expressing RGD peptide receptors). dND-PG and dND-PG-RGD showed good aqueous solubility and cytocompatibitlity. Subsequently, the anticancer agent doxorubicin (DOX) was loaded through acid-labile hydrazone linkage to yield dND-PG-DOX and dND-PG-RGD-DOX Their cellular uptake and cytotoxicity were compared against DOX in A549 cells and U937 macrophages. It was found that dND-PG-DOX uptake was substantially reduced, displaying little toxicity in either type of cells by virtue of PG coating, whereas dND-PG-RGD-DOX exerted selective toxicity to A549 cells over U937 macrophages that are otherwise highly sensitive to DOX. Finally, dND-PG was demonstrated to have little influence on U937 macrophage cell functions, except for a slight increase of TNF-alpha production in resting U937 macrophages. dND-PG is a promising drug carrier for realization of highly selective drug delivery in tumor cells through specific uptake mechanisms, with minimum uptake in and influence on macrophages. (C) 2014 Elsevier Ltd. All rights reserved.
• Influence of MWCNTs to Myocardial Contraction Rhythms on Differentiation of ES-D3 Cells in Three-dimensional Culture

  Koichi IMAI, Tsubasa SHIRAI, Fumio WATARI, Tsukasa AKASAKA, Tetsunari NISHIKAWA, Tomoharu OKAMURA, Akio TANAKA, Kazuhiko SUESE, Fumiya OGAWA, Yoshitomo HONDA, Hirofumi SAWAI, Hiromasa TAKASHIMA

  Nano Biomedicine 6 (1) 27 - 34 2014/06 [Refereed][Not invited]
  
• Graphene oxide coating facilitates the bioactivity of scaffold material for tissue engineering

  Erika Nishida, Hirofumi Miyaji, Hiroko Takita, Izumi Kanayama, Maiko Tsuji, Tsukasa Akasaka, Tsutomu Sugaya, Ryuji Sakagami, Masamitsu Kawanami

  JAPANESE JOURNAL OF APPLIED PHYSICS 53 (6) 06JD04  0021-4922 2014/06 [Refereed][Not invited]
   

  Carbon-based nanomaterials are being investigated for biomedical applications. Graphene oxide (GO), a monolayer of carbon, holds promise as a tissue engineering substrate due to its unique physicochemical properties. The aim of this study was to evaluate the effect of a GO coating on cell proliferation and differentiation in vitro. We also assessed the bioactivities of collagen scaffolds coated with different concentrations of GO in rats. The results showed that GO affects both cell proliferation and differentiation, and improves the properties of collagen scaffolds. Subcutaneous implant tests showed that low concentrations of GO scaffold enhances cell in-growth and is highly biodegradable, whereas high concentrations of GO coating resulted in adverse biological effects. Consequently, scaffolds modified with a suitable concentration of GO are useful as a bioactive material for tissue engineering. (C) 2014 The Japan Society of Applied Physics
• Preparation and biocompatibilities of luminescent europium-doped yttria and titania nanoparticles

  Shigeaki Abe, Yusuke Hamba, Atsushi Hyono, Shuichi Yamagata, Motohiro Uo, Junichiro Iida, Takayuki Kiba, Akihiro Murayama, Tsukasa Akasaka, Fumio Watari

  JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 122 (1423) 216 - 221 1882-0743 2014/03 [Refereed][Not invited]
   

  In this study, we prepared two types of europium (Eu)-doped nanoparticle, yttoria and titania and investigated their photo-physical properties and biocompatibilities. These particles do not inhibit cell culture, even at higher concentrations. The obtained nanoparticles had a strong and narrow red photo-luminescent peak. The narrow emission was observed even when the particles were uniformly doped into a polymer film. These results suggest that they can be used for applications not only in optoelectronic devices but also in biomedical devices for bioimaging and luminescent biomedical materials. (C)2014 The Ceramic Society of Japan. All rights reserved.
• Bone enhancing effect of titanium-binding proteins isolated from bovine bone and implanted into rat calvaria with titanium scaffold

  Yoshinori Kuboki, Toshitake Furusawa, Masaaki Sato, Yongkun Sun, Hidero Unuma, Shigeaki Abe, Ryuichi Fujisawa, Tsukasa Akasaka, Fumio Watari, Hiroko Takita, Rachel Sammons

  BIO-MEDICAL MATERIALS AND ENGINEERING 24 (3) 1539 - 1548 0959-2989 2014 [Refereed][Not invited]
   

  Based on our previous finding that a chromatography with titanium beads selectively binds phosphoproteins, including caseins, phosvitin and dentin phosphoproteins, we investigated whether bone phosphoproteins also bind to titanium. Bovine bone matrix proteins were extracted with 2 M urea/PBS after demineralization. The 2 M urea extract was directly applied to the titanium chromatography column as reported. The chromatogram showed an initial large peak at breakthrough position (non-binding fraction) and a smaller second peak eluted later (titanium-binding fraction). Both peaks were analyzed by SDS polyacrylamide gel electrophoresis. Stains-all staining which preferentially identifies phospho-proteins revealed that the first peak contained no positively stained band, while the second peak showed 4 or 5 distinctive bands indicative of bone phosphoproteins. To investigate the biological functions of the titanium-binding bone proteins (TiBP), we implanted them into calvaria of rats, combined with titanium web (TW), a highly porous titanium scaffold of thin titanium-fibers. Bone TiBP induced significantly enhanced bone formation, and new bone appeared connected directly to titanium fibers, accompanied by active blood vessel formations. Control TW alone did not induce bone formation within the titanium framework. These results demonstrate that the bone titanium-binding proteins include phosphoproteins which enhance bone formation when implanted into bone with titanium.
• Comparative study of bioactivity of collagen scaffolds coated with graphene oxide and reduced graphene oxide

  Izumi Kanayama, Hirofumi Miyaji, Hiroko Takita, Erika Nishida, Maiko Tsuji, Bunshi Fugetsu, Ling Sun, Kana Inoue, A. Sako Ibara, Tsukasa Akasaka, Tsutomu Sugaya, Masamitsu Kawanami

  INTERNATIONAL JOURNAL OF NANOMEDICINE 9 3363 - 3373 1178-2013 2014 [Refereed][Not invited]
   

  Background: Graphene oxide (GO) is a single layer carbon sheet with a thickness of less than 1 nm. GO has good dispersibility due to surface modifications with numerous functional groups. Reduced graphene oxide (RGO) is produced via the reduction of GO, and has lower dispersibility. We examined the bioactivity of GO and RGO films, and collagen scaffolds coated with GO and RGO. Methods: GO and RGO films were fabricated on a culture dish. Some GO films were chemically reduced using either ascorbic acid or sodium hydrosulfite solution, resulting in preparation of RGO films. The biological properties of each film were evaluated by scanning electron microscopy (SEM), atomic force microscopy, calcium adsorption tests, and MC3T3-E1 cell seeding. Subsequently, GO-and RGO-coated collagen scaffolds were prepared and characterized by SEM and compression tests. Each scaffold was implanted into subcutaneous tissue on the backs of rats. Measurements of DNA content and cell ingrowth areas of implanted scaffolds were performed 10 days post-surgery. Results: The results show that GO and RGO possess different biological properties. Calcium adsorption and alkaline phosphatase activity were strongly enhanced by RGO, suggesting that RGO is effective for osteogenic differentiation. SEM showed that RGO-modified collagen scaffolds have rough, irregular surfaces. The compressive strengths of GO-and RGO-coated scaffolds were approximately 1.7-fold and 2.7-fold greater, respectively, when compared with the non-coated scaffold. Tissue ingrowth rate was 39% in RGO-coated scaffolds, as compared to 20% in the GO-coated scaffold and 16% in the non-coated scaffold. Conclusion: In summary, these results suggest that GO and RGO coatings provide different biological properties to collagen scaffolds, and that RGO-coated scaffolds are more bioactive than GO-coated scaffolds.
• Application of Fourier Transform for Analysis of Surface Topographic Properties of Dental Zirconia

  Naoyoshi TARUMI, Tsukasa AKASAKA, Fumio WATARI

  Nano Biomedicine 5 (2) 85 - 94 2013/12 [Refereed][Not invited]
  
• Preparation and Properties of Fluorescent Orthodontic Adhesives Containing Y2O3:Eu3+ Particles

  Yusuke HAMBA, Shuichi YAMAGATA, Tsukasa AKASAKA, Motohiro UO, Junichiro IIDA, Fumio WATARI

  Nano Biomedicine 5 (2) 75 - 84 2013/12 [Refereed][Not invited]
  
• An Attempt to Study of the Embryotoxicity by the Diamond Particles of Dental Diamond Points with the Embryonic Stem Cell Test

  Koichi IMAI, Fumio WATARI, Tsukasa AKASAKA, Kazuhiko SUESE, Fumiya OGAWA, Hirofumi SAWAI, Hiromasa TAKASHIMA

  Nano Biomedicine 5 (2) 104 - 108 2013/12 [Refereed][Not invited]
  
• The effects of the coating of anodized titanium with multi-walled carbon nanotuves on bone formation.

  Inoue S, Uo M, Sakairi M, Hirata E, Lee M.H, Bae T.S, Akasaka T, Watari F, Yokoyama A

  Key Engineering Materials 529-530 621 - 624 1013-9826 2013/11 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) have excellent chemical, physical, and biological properties such as strong cell adhesion, protein adsorption and cell proliferation in vitro. Excellent osteocompatibility for the CNT monolith was also reported in vivo. The purpose of this study was to evaluate the effects of anodized titanium coated with multiwalled CNTs (MWCNTs) on human osteosarcoma Saos2 cells and bone tissue. Saos2 cells on CNT-Ti showed excellent proliferation with extension of cell morphology in all directions. CNT-Ti wire was implanted in the bone marrow of femurs of rats. At 2 weeks after surgery, histological investigations revealed that bone tissue attached to the surface of the CNT-Ti directly. Thus the surface modification of anodized Ti by MWCNTs can be effective for bone formation.
• An In Vitro Evaluation of the Biological Effects of Carbon Nanotube-Coated Dental Zirconia

  Wen Kou, Tsukasa Akasaka, Fumio Watari, Göran Sjögren

  ISRN Dentistry 2013 296727 - 296727 2013/07 [Refereed][Not invited]
   

  THE PURPOSE OF THIS STUDY IS TO EVALUATE FUNCTIONALIZED MULTIWALLED CARBON NANOTUBES (FMWCNTS) AS A POTENTIAL COATING MATERIAL FOR DENTAL ZIRCONIA FROM A BIOLOGICAL PERSPECTIVE: its effect on cell proliferation, viability, morphology, and the attachment of an osteoblast-like cell. Osteoblast-like (Saos-2) cells were seeded on uncoated and fMWCNT-coated zirconia discs and in culture dishes that served as controls. The seeding density was 10(4) cells/cm(2), and the cells were cultured for 6 days. Cell viability, proliferation and attachment of the Saos-2 cells were studied. The results showed that Saos-2 cells were well attached to both the uncoated and the fMWCNT-coated zirconia discs. Cell viability and proliferation on the fMWCNT-coated zirconia discs were almost the same as for the control discs. Better cell attachment was seen on the fMWCNT-coated than on the uncoated zirconia discs. In conclusion, fMWCNTs seem to be a promising coating material for zirconia-based ceramic surfaces to increase the roughness and thereby enhance the osseointegration of zirconia implants.
• An Evaluation of Fluorescent Orthodontic Adhesives Containing Eu-doped ZnO at Room Temperature

  Shuichi YAMAGATA, Hiroshi IWASAKI, Yusuke HAMBA, Ko NAKANISHI, Natsumi USHIJIMA, Shigeaki ABE, Tsukasa AKASAKA, Fumio WATARI, Junichiro IIDA

  Nano Biomedicine 5 (1) 31 - 38 2013/06 [Refereed][Not invited]
  
• Adsorption behavior of albumin and other proteins on carbon nanotubes studied by chromatography

  M. Morikawa, Y. Kuboki, T. Akasaka, S. Abe, H. Takita, F. Watari

  Key Engineering Materials 529-530 (1) 615 - 620 1013-9826 2013 [Refereed][Not invited]
   

  For application of carbon nanotubes (CNTs) as biomaterials, it is important to clarify the interaction between CNTs and proteins, which may affect on cell proliferation and differentiation. In this study, the adsorption behavior was investigated for representative proteins, bovine serum albumin, lysozyme and fetal bovine serum by using chromatography system. It was also aimed whether the different treatment conditions of CNTs affected the adsorption of proteins. CNTs used for this study had a straight shape and about 70nm in a diameter from SEM observation. There was not much difference between untreated and treated CNTs from SEM images. In chromatography experiments, all the proteins of albumin, lysozyme and serum were eluted immediately after injected to the column of untreated CNTs. Second elution appeared after buffer was changed from phosphate saline buffer to 25mM sodium hydroxide (NaOH). The same tendency was confirmed for CNTs with only acid treatment. However the eluted peaks became remarkably smaller after the column was changed to CNTs with thermal and twice acid treatments. These results indicated that treatment conditions for CNTs affected the adsorption behavior of proteins. © (2013) Trans Tech Publications, Switzerland.
• Influence of micro-/nano- particles on osteoblast-like cells: A static and time lapse observation

  Nobuki Iwadera, Shigeaki Abe, Tsukasa Akasaka, Yasutaka Yawaka, Fumio Watari

  BIOCERAMICS 24 529-530 374 - + 1013-9826 2013 [Refereed][Not invited]
   

  Cytotoxicity and cell behavior to micro / nano particles of TiO2 and CuO was evaluated using the viability measurement and time-lapse observation. After cultured, osteoblastic cells MC3T3-E1 were exposed to particles. After 24 hour exposure, their morphology was observed using a SEM and the viability was measured. Cells exposed to TiO2 indicated no or very low decrease of viability. The results were independent of the particle size. On the other hand, the viability of cells exposed to CuO decreased with the concentration, and showed the size dependence. The nano-sized CuO indicated higher toxicity compared with micro-sized one. Dynamic behavior of cells exposed to nano particles, was succeeded to observe in a time-lapse method for 24 hours. The observation showed that the cells exposed to CuO became dead after forming a spherical shape. This is consistent with the image taken by SEM. Time-lapse observation made it possible to see the dynamic reaction process from cell contact to particles at first, the following cell activity response and finally to cell death, which revealed a considerably different morphology from the static cell observed after fixation by conventional method.
• Biocompatibility and biodistribution of several nano-sized ceramics particles

  Shigeaki Abe, Yusaku Hamba, Nobuki Iwadera, Tsukasa Akasaka, Shuichi Yamagata, Yasutaka Yawaka, Junichiro Iida, Motohiro Uo, Tetsu Yonezawa, Fumio Watari

  BIOCERAMICS 24 529-530 625 - + 1013-9826 2013 [Refereed][Not invited]
   

  We succeeded in determination the biodistribution of several nano-sized particles administered to mice through the tail vein. After administration, these particles were observed in the lung, liver and spleen. The distribution behaviors depend upon not only chemical species but also the particles size. To estimate their cytocompatibility, these particles were exposed to osteoblastic cell at several concentrations. When the concentration reached at 10 ppm, their viability remained at 80% or more even nano-sized particle contained rare earth element. Only CuO particles indicated the viability decrease. The effect depended on the particle size. These results suggested that the chemical species played a dominant key in the biodistribution and biocompatibility of nanoparticles compared with the size-effect.
• Murine macrophage RAW264.7 cells response for the carbon nanotubes immobilized on substrate

  Tsukasa Akasaka, Shigeaki Abe, Fumio Watari

  Key Engineering Materials 529-530 (1) 379 - 384 1013-9826 2013 [Not refereed][Not invited]
   

  The reports on cytotoxic studies of carbon nanotubes (CNTs) increased exponentially. In the present study, we investigate murine macrophage RAW264.7 cell response for the CNTs immobilized on a polystyrene substrate. We prepared CNT-coated dishes, and estimate the interaction of RAW264.7 cells with CNTs by cell adhesion, proliferation assay, and measurement of TNF-α production. As a result, the highest cell adhesion and proliferation was observed on a commercially cell culture polystyrene dish, while CNT-coated dish indicate slightly lower activity of them. Moreover, amount of production of TNF-α on the CNT-coated dishes was considerable lower than that in the case of lipopolysaccharide (LPS) addition as a control. These results indicated that CNT-coated dishes could not show strong cytotoxicity for RAW264.7 cells in vitro. © (2013) Trans Tech Publications, Switzerland.
• Applications of micro/nano patterned bio-materials in dental field

  T. Akasaka, Fumio Watari

  Hokkaido Journal of Dental Science 32 (2) 189 - 191 2013 [Refereed][Not invited]
  
• Investigation of biodistribution behavior of platinum particles in mice: Correlation between inductively coupled plasma-atomic emission spectroscopy and X-ray scanning analytical microscopy

  Shigeaki Abe, Chika Koyama, Mami Mutoh, Tsukasa Akasaka, Motohiro Uo, Fumio Watari

  APPLIED SURFACE SCIENCE 262 125 - 128 0169-4332 2012/12 [Refereed][Not invited]
   

  In this study, we investigated the biodistribution of platinum (Pt) microparticles in mice. The particles were administered through the tail vein, and then the biodistribution behavior was observed using inductively coupled plasma-atomic emission spectroscopy (ICP) and scanning X-ray analytical microscopy (XSAM). The administered particles quickly reached the spleen, liver, and lung at a constant ratio, and the ratio remained constant for four weeks. We also estimated the correlation between XSAM and ICP measurement. The relative ratio of XSAM intensity showed strong correlation with the relative ratio of Pt concentration in organs. (c) 2012 Elsevier B.V. All rights reserved.
• Morphology, size distribution and elemental composition of several dental debris

  Shigeaki Abe, Nobuki Iwadera, Mitsue Esaki, Ken-Ichi Aoyama, Tsukasa Akasaka, Motohiro Uo, Manabu Morita, Yasutaka Yawaka, Fumio Watari

  APPLIED SURFACE SCIENCE 262 248 - 252 0169-4332 2012/12 [Refereed][Not invited]
   

  We investigated morphologies, size distributions and elemental compositions of dental debris formed by cutting/grinding teeth or dental alloys. The average size of debris formed by cutting/grinding dental alloy was around 100 mu m and that of teeth was 20 mu m. The debris formed by grinding with diamond or carborundum point had isotropic irregular shape, while the debris formed by cutting with carbide bar had characteristic lathe-cut shape. The elemental analysis indicated that the debris formed by grinding dental alloy with carborundum point consisted of not only the particles of the alloy but also the particles of Si compounds with the size of around 10 mu m. The particles of Si compounds would be formed by abrasion of the grinding instrument (carborundum, SiC). Similarly, the debris formed by grinding with diamond point also contained submicro-sized particles consisting of C compounds. The results indicate that the morphology and composition of dental debris are varied depending on the combination between the workpiece and the cutting/grinding materials and that the dental debris consist of both the workpiece and the cutting/grinding materials in some combination. In addition, some of the debris of tooth had the size less than 2 mu m, which has a potential to induce inflammation. Though the inflammation can be expected at low level, it is required to investigate the details in future. (c) 2012 Elsevier B.V. All rights reserved.
• Evaluation of Adhesion between Material and Epithelium using a Three-dimensional Human Epidermal Model

  Kazunori FURUHASHI, Tsukasa AKASAKA, Yoshimasa KITAGAWA, Fumio WATARI

  Nano Biomedicine 4 (2) 76 - 84 1883-5198 2012/12 [Refereed][Not invited]
   

  The use of dental implants currently entails problems associated with lack of adhesion to the oral mucosa at the point of abutment, which differs from that of natural teeth. Usually, the experimental evaluation of adhesion between test implant materials and soft tissue requires animal experiments. In this study, to facilitate easier evaluation, adhesion experiments were performed using a three-dimensional (3D) in vitro epidermal cell culture model. The implant materials examined were nano hydroxyapatite (nHAp) coated polyethylene terephthalate (PET), uncoated PET, zirconia, and titanium. The nHAp particles exhibited high cell adhesion, and nHAp coated PET exhibited high tissue-adhesion in the 3D epidermal cell culture in vitro. Zirconia exhibited substantial tissue adhesion to the 3D epithelial tissue, but titanium exhibited little adhesion. This 3D in vitro epidermal cell culture model could be used instead of animal experiments to facilitate easier evaluation of adhesion between tissue and materials, and it could be useful in screening tests for the development of tissue adhesive materials and processing conditions.
• The effect of enhancing the hydrophobicity of OMMT on the characteristics of PMMA/OMMT nanocomposites

  Shuichi Yamagata, Yusuke Hamba, Tsukasa Akasaka, Natsumi Ushijima, Motohiro Uo, Junichiro Iida, Fumio Watari

  APPLIED SURFACE SCIENCE 262 56 - 59 0169-4332 2012/12 [Refereed][Not invited]
   

  Transparent poly(methyl methacrylate)/organically modified montmorillonite (PMMA/OMMT) nanocomposites were fabricated using a solution intercalation method. Two grades of OMMT modified with quaternary alkylammonium ions and containing different amounts of organic matter, NZ70 and NX, were used. X-ray diffraction patterns showed that the peaks regarded as a (0 0 1) d-spacing and a second peak were shifted toward lower 2 theta values, implying the expansion or the partial exfoliation of the silicate layers, respectively. TEM images showed that the silicate platelets were largely well dispersed independent of the hydrophobicity, although some aggregates were observed. The flexural modulus of the PMMA/OMMT nanocomposites increased favorably with an increasing amount of OMMT of either grade. However, only the NX displayed comparable strain at breakage to that of the PMMA. These results suggest that the highly hydrophobic grade NX shows great promise for use in nanocomposites made via solution intercalation. (c) 2012 Elsevier B.V. All rights reserved.
• Carbon nanotube-coating accelerated cell adhesion and proliferation on poly (L-lactide)

  Eri Hirata, Tsukasa Akasaka, Motohiro Uo, Hiroko Takita, Fumio Watari, Atsuro Yokoyama

  APPLIED SURFACE SCIENCE 262 24 - 27 0169-4332 2012/12 [Refereed][Not invited]
   

  The surface of a polylactic acid (PLLA) was coated multiwalled carbon nanotubes (MWCNTs) in order to improve the surface properties. In addition, its surface characteristics and cell culturing properties were examined. Whole surface of PLLA was homogeneously covered by MWCNTs maintained a unique tubular structure. MWCNT-coated PLLA showed remarkable higher wettability than uncoated PLLA. Human osteosarcoma cell line (Saos2) adhered well on the CNT-coated PLLA whereas there are few cells attached on the uncoated PLLA at 2 h after seeding. The number of the cells on uncoated PLLA was still smaller than on the MWCNT-coated PLLA at 1 and 3 days. Moreover, The DNA content in the cells attached to the MWCNT-coated PLLA was significantly higher than that on the uncoated PLLA (p < 0.05) at 1 and 3 days. There was no significant difference between the scaffolds for ALP activity normalized by DNA content at both term (p > 0.1). Therefore MWCNT-coating on PLLA improved the surface wettability and initial cell attachment at early stage. (c) 2012 Elsevier B.V. All rights reserved.
• Deposition of TiC film on titanium for abrasion resistant implant material by ion-enhanced triode plasma CVD

  Yuhe Zhu, Wei Wang, Xingya Jia, Tsukasa Akasaka, Susan Liao, Fumio Watari

  APPLIED SURFACE SCIENCE 262 156 - 158 0169-4332 2012/12 [Refereed][Not invited]
   

  Deposition of titanium carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method using a TiCl4 + CH4 + H-2 gas mixture. Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. X-ray diffraction (XRD) showed that the specimen was consisted of TiC and Ti. Carbide layer of about 6 mu m thickness was observed on the cross section of the specimen by scanning electron microscopy (SEM). The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance. (c) 2012 Elsevier B.V. All rights reserved.
• Phytotoxicity of multi-walled carbon nanotubes assessed by selected plant species in the seedling stage

  Parvin Begum, Refi Ikhtiari, Bunshi Fugetsu, Makoto Matsuoka, Tsukasa Akasaka, Fumio Watari

  APPLIED SURFACE SCIENCE 262 120 - 124 0169-4332 2012/12 [Refereed][Not invited]
   

  Abundant experimental data have shown that multi-walled carbon nanotubes (MWNTs) are toxic to plants, but the potential impacts of exposure remain unclear. The objective of the present study was to evaluate possible phytotoxicity of MWNTs at 0, 20, 200, 1000, and 2000 mg/L with red spinach, lettuce, rice, cucumber, chili, lady's finger, and soybean based on root and shoot growth, cell death, and electrolyte leakage at the seedling stage. After 15 days of hydroponic culture, the root and shoot lengths of red spinach, lettuce, and cucumber were significantly reduced following exposure to 1000 mg/L and 2000 mg/L MWNTs. Similar toxic effects occurred regarding cell death and electrolyte leakage. Red spinach and lettuce were most sensitive to MWNTs, followed by rice and cucumber. Very little or no toxic effects were observed for chili, lady's finger, and soybean. (c) 2012 Elsevier B.V. All rights reserved.
• In vitro study of cell differentiation by two type mouse embryo stem cells on mono- and multilayer nanocarbon tubes

  Koichi Imai, Tsukasa Akasaka, Fumio Watari, Akito Tanoue, Kazuaki Nakamura, Kazuhiko Suese, Hiromasa Takashima, Tetsunari Nishikawa, Akio Tanaka, Shoji Takeda

  APPLIED SURFACE SCIENCE 258 (22) 8444 - 8447 0169-4332 2012/09 [Refereed][Not invited]
   

  The effects of nanomaterials on human reproduction and development remain unknown. The risks of nanomaterials for future generations should be elucidated. Thus, it is important to establish an experimental method to accurately examine embryotoxicity. We previously investigated the myocardial cell differentiation of ES-D3 cells using monolayer (SWCNTs) and multilayer (MWCNTs) nanocarbon tubes. As a result, in spite of having the same carbon composition, the effects on the cell differentiation levels differed between the tubes. We investigated their cell differentiation and cytotoxic effects on EL M3 and ES-R1-EGFP B2/EGFP cells, which require feeder cells. As a result, myocardial pulse rates differed between the presence of SWCNTs and MWCNTs even when feeder cells existed between the samples and cells. The different surface structures of SWCNTs and MWCNTs may have influenced ES cell differentiation. (C) 2012 Elsevier B. V. All rights reserved.
• Carbonate Ion Induced Calcification Using Biomimetic Enzymes with Active Reaction Center of Carbonc Anhydrase

  Shigeaki ABE, Minoru YOHDA, Aki NISHIYAMA, Mitsunori NAKATANI, Yuhei FUJII, Arisa KUSUHARA, Emi YAMATOYA, Tomoki ISHIDA, Tsukasa AKASAKA, Motohiro UO, Fumio WATARI, Daisuke HAYASHI, Tomoya TAKADA

  Nano Biomedicine 4 (1) 29 - 34 2012/06 [Refereed][Not invited]
  
• Effect of Pretreatments to Carbon Nanotubes on Protein Adsorption

  Mai MORIKAWA, Yoshinori KUBOKI, Tsukasa AKASAKA, Sigeaki ABE, Fumio WATARI

  Nano Biomedicine 4 (1) 35 - 41 2012/06 [Refereed][Not invited]
  
• Introduction of Rare-Earth-Element- Containing ZnO Nanoparticles into Orthodontic Adhesives

  Shuichi YAMAGATA, Yusuke HAMBA, Ko NAKANISHI, Shigeaki ABE, Tsukasa AKASAKA, Natsumi USHIJIMA, Motohiro UO, Junichiro IIDA, Fumio WATARI

  Nano Biomedicine 4 (1) 11 - 17 2012/06 [Refereed][Not invited]
  
• Carbon nanotube-coated silicone as a flexible and electrically conductive biomedical material

  Makoto Matsuoka, Tsukasa Akasaka, Yasunori Totsuka, Fumio Watari

  MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 32 (3) 574 - 580 0928-4931 2012/04 [Refereed][Not invited]
   

  Artificial cell scaffolds that support cell adhesion, growth, and organization need to be fabricated for various purposes. Recently, there have been increasing reports of cell patterning using electrical fields. We fabricated scaffolds consisting of silicone sheets coated with single-walled (SW) or multi-walled (MW) carbon nanotubes (CNTs) and evaluated their electrical properties and biocompatibility. We also performed cell alignment with dielectrophoresis using CNT-coated sheets as electrodes. Silicone coated with 10 mu g/cm(2) SWCNTs exhibited the least sheet resistance (0.8 k Omega/sq); its conductivity was maintained even after 100 stretching cycles. CNT coating also improved cell adhesion and proliferation. When an electric field was applied to the cell suspension introduced on the CNT-coated scaffold, the cells became aligned in a pearl-chain pattern. These results indicate that CNT coating not only provides electro-conductivity but also promotes cell adhesion to the silicone scaffold: cells seeded on the scaffold can be organized using electricity. These findings demonstrate that CNT-coated silicone can be useful as a biocompatible scaffold. (C) 2011 Elsevier B.V. All rights reserved.
• Comparison of biodistribution and biocompatibility of gelatin-coated copper nanoparticles and naked copper oxide nanoparticles

  Shigeaki Abe, Nobuki Iwadera, Takashi Narushima, Yoshiki Uchida, Motohiro Uo, Tsukasa Akasaka, Yasutaka Yawaka, Fumio Watari, Tetsu Yonezawa

  e-Journal of Surface Science and Nanotechnology 10 33 - 37 1348-0391 2012/03/17 [Refereed][Not invited]
   

  In this study, we investigated the biocompatibility of gelatin-coated copper nanoparticles. To estimate their cytotoxicity, the coated copper nanoparticles were exposed to osteoblastic cells. The cell proliferation remained above 80% even when the particles concentration increased. When uncoated copper oxide nanoparticles were exposed to the cells, the proliferation ratio rapidly decreased with the concentration reaching 20% under the same conditions. To determine their biodistribution, the nanoparticles were administered to mice through their tail veins. The particles were subsequently found in some organs using an energy-dispersed X-ray spectrometer and inductively coupled plasma-atomic emission spectroscopy. The polymer-coated nanoparticles were observed in the lung, liver and spleen. They were also detected in the urine at higher concentrations than the copper oxide nanoparticles. Thus, the polymer coating is expected to improve biocompatibility by virtue of the excellent cytocompatibility and acceleration of the excretion process. © 2012 The Surface Science Society of Japan.
• Internal Diffusion of Biocompatible Polymer-Coated Inorganic Nanoparticles in Mice

  S. Abe, A. Sakaki, T. Narushima, Y. Uchida, T. Akasaka, M. Uo, T. Yonezawa, F. Watari

  Key Engneering Materials 493-494 752 - 756 2012 [Not refereed][Not invited]
  
• Interaction between titanium and phosphoproteins revealed by chromatography column packed with titanium beads

  Yoshinori Kuboki, Toshitake Furusawa, Masaaki Sato, Yongkun Sun, Hidero Unuma, Ryuichi Fujisawa, Shigeaki Abe, Tsukasa Akasaka, Fumio Watari, Hiroko Takita, Rachel Sammons

  BIO-MEDICAL MATERIALS AND ENGINEERING 22 (5) 283 - 288 0959-2989 2012 [Refereed][Not invited]
   

  The biochemical mechanism behind the strong binding between titanium and living bone has not been fully elucidated, in spite of worldwide clinical application of this phenomenon. We hypothesized that one of the core mechanisms may reside in the interaction between certain proteins in the host tissues and the implanted titanium. To verify the interaction between titanium and proteins, we chose the technique of chromatography in that titanium spherical beads (45 mu m) were packed into a column to obtain a bed volume of 16 x 50 mm, which was eluted with phosphate buffered saline (PBS) and a straight gradient system made by using PBS and 25 mM NaOH. Fetal calf serum, albumin, lysozyme, casein, phosvitin and dentin phosphoprotein (phosphophoryn) were applied to the column. Most part of albumin and lysozyme eluted with the breakthrough peak, indicating practically no affinity to titanium. Fetal bovine serum also eluted mostly as the breakthrough peak, but distinct retained peak was observed. On the other hand, alpha-casein, phosvitin and phosphophoryn exhibited a distinct retained peak separated from the breakthrough peak. We proposed that phosphate groups (phosphoserines) in the major phosphoproteins, alpha-casein, phosvitin and phosphophoryn may be involved in the binding of these proteins with titanium.
• Biodistribution of Aqueous Suspensions of Carbon Nanotubes in Mice and Their Biocompatibility

  Shigeaki Abe, Sachiko Itoh, Daisuke Hayashi, Toshihisa Kobayashi, Takayuki Kiba, Tsukasa Akasaka, Motohiro Uo, Yasutaka Yawaka, Shin-Ichiro Sato, Fumio Watari, Tomoya Takada

  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 12 (1) 700 - 706 1533-4880 2012/01 [Refereed][Not invited]
   

  In this study, we prepared two-types of water-dispersible carbon nanotubes (CNTs) and investigated their biodistribution in mice as well as bio-/cyto-compatibility. After administration, their organs were excised at various post-injection times, then observed using both optical and transmission electron microscopy (TEM). The color of the liver and lung markedly darkened, suggesting that administered CNTs reached these organs. By TEM observation, the CNTs were found in the liver and lung. They were observed even in the kidney and spleen, though their distributions in those organs were very low compared with that in liver and lung. Therefore, most of the administered CNTs would be accumulated in the liver or lung. However, the time profile of the body weight of CNT-administered mice was close to that of control mice. In addition, we estimated the cytocompatibility of the water-dispersible CNTs for hepatocytes. According to a TNF-alpha assay of the cells cultured with CNTs, the expression level was almost the same as that of the control. These results suggested that the water-dispersible CNTs have good bio-/cyto-compatibility under this condition.
• Biodistribution and Biocompatibility of Poly(lactic acid)-coated SiO2 Particle

  Shigeaki ABE, Akiko SASAKI, Nobuki IWADERA, Tsukasa AKASAKA, Motohiro UO, FumioI WATARI

  Nano Biomedicine 3 (2) 300 - 305 2011/11 [Refereed][Not invited]
  
• Optical and Mechanical Properties of Poly (methyl methacrylate) / Montmorillonite Nanocomposites

  Shuichi YAMAGATA, Yusuke HAMBA, Tsukasa AKASAKA, Motohiro UO, Junichiro IIDA, Fumio WATARI

  Nano Biomedicine ナノ・バイオメディカル学会 3 (1) 217 - 223 2011/08 [Refereed][Not invited]
   

  Transparent poly (methyl methacrylate)/organically modified montmorillonite (PMMA/OMMT) nanocomposites were fabricated using a solution intercalation method. OMMT was modified with quaternary alkylammonium ions. The haze values, which are the ratios of diffuse transmittance to total light transmittance via the nanocomposites, gradually increased with an increasing amount of OMMT; however, the deterioration of total light transmittance was maintained within a narrow range. X-ray diffraction patterns showed that a peak regarded as a (001) d-spacing or a second peak corresponding to (002) plane was shifted toward lower 2θ values indicating the penetration of the PMMA polymer chains into the interlayer regions of OMMT. Board-shaped specimens used for the flexural tests were fabricated by compression molding at 230°C. The specimens were sufficiently transparent for their use as esthetic orthodontic wires. The flexural modulus of the PMMA/OMMT nanocomposites increased favorably with an increasing amount of OMMT. It is reasonable to consider that the addition of OMMT to the nanocomposites effectively improves the stiffness of PMMA without seriously deteriorating its flexibility.
• Versatile Surface Modification by Carbon Nanotubes Through an Amide-bond Formation

  Shigeaki ABE, Katsutoshi NAKAYAMA, Hirohisa KOBAYASHI, Takayuki KIBA, Tsukasa AKASAKA, Shin-ichiro SATO, Motohiro UO, Fumio WATARI, Tomoya TAKADA

  Nano Biomedicine ナノ・バイオメディカル学会 3 (1) 208 - 216 2011/08 [Refereed][Not invited]
   

  There is considerable investigation into the applications of carbon nanotubes because of their valuable properties. In this study, our goal was to develop several carbon nanotube (CNT)-coated substrates through an amide-bonding process. We prepared polycarboxylated multi-walled CNTs via a carboxylation reaction and then CNT derivatives were tethered to amino groups presented on a titanium, gold or glass substrate in the presence of a condensation agent. The obtained substrates were characterized with a Raman microscope, an atomic force microscope (AFM) and a scanning electron microscope (SEM). Raman mapping images indicated that the CNTs existed on the substrate surface homogeneously, and AFM and SEM observation revealed that the CNTs coating the surfaces had a three-dimensional network nanostructure. The CNTs remained on the surface even after ultrasonication treatment in organic solvent. However, they were removed from the substrate surface after soaking in NaOH aqueous solution. This result suggested that the CNTs were tethered to the substrate through amide bonding.
• Study of In Vitro Embryotoxicity Potential by Two Type Nano Titanium Dioxide

  Koichi IMAI, Tsukasa AKASAKA, Fumio WATARI, Akito TANOUE, Kazuaki NAKAMURA, Kazuhiko SUESE, Hiromasa TAKASHIMA, Tetsunari NISHIKAWA, Akio TANAKA, Shoji TAKEDA

  Nano Biomedicine ナノ・バイオメディカル学会 3 (1) 224 - 230 2011/08 [Refereed][Not invited]
   

  Nano and submicron titanium dioxides are widely used as ingredients of sun screen. Thus, its reproductive and developmental toxicities in humans are of concern. We used two kinds of nano titanium dioxides, involving different production methods and surface coatings. The embryotoxicities of these nano titanium dioxides were determined based on inhibitory effects on the cardiomyocyte differentiation of mouse Embryonic Stem cells. As ultrafine titanium dioxide, titanium dioxide (particle diameter, 0.03-0.05 μm) produced by the sintering method (T1) and that (particle diame-ter, 0.01-0.02 μm) produced by the wet method (T2) were used. T2 may cause little developmental toxicity because it has no potent inhibitory effects on cardiomyocyte differentiation. However, T1 should be further investigated.
• Multiwalled carbon nanotube-coating of 3D collagen scaffolds for bone tissue engineering

  Eri Hirata, Motohiro Uo, Hiroko Takita, Tsukasa Akasaka, Fumio Watari, Atsuro Yokoyama

  CARBON 49 (10) 3284 - 3291 0008-6223 2011/08 [Refereed][Not invited]
   

  Surface coating treatment with multiwalled carbon nanotubes (MWCNTs) was applied to 3D collagen scaffold for bone tissue engineering. Rat primary osteoblasts (ROBs) were cultured on an MWCNT-coated collagen sponge (MWCNT-coated sponge) in a 3D dynamic flow cell culture system and differentiation markers were measured. Alkaline phosphatase activity at 1 day, and calcium and osteopontin contents of the MWCNT-coated sponges at 7 days were significantly higher than those of uncoated sponges. ROBs on the MWCNT-coated sponge differentiated earlier than on the uncoated sponge. In addition, the tissue response to the MWCNT-coated sponge was evaluated. Slight inflammation was observed around MWCNTs at 7 and 28 days after implantation in subcutaneous tissue. Significantly more bone formation was observed around the MWCNT-coated sponges than around the uncoated sponges and new bone attached to MWCNTs directly at 28 and 56 days after implantation in the femur. Moreover, at 28 days after implantation of the MWCNT-coated sponge with osteoblasts cultured for 1 day, bone tissues were successfully formed in the pores according to its honeycomb structure. Therefore, MWCNT coating appears to be effective for bone tissue engineering. (C) 2011 Elsevier Ltd. All rights reserved.
• Maintenance of hemiround colonies and undifferentiated state of mouse induced pluripotent stem cells on carbon nanotube-coated dishes

  Tsukasa Akasaka, Atsuro Yokoyama, Makoto Matsuoka, Takeshi Hashimoto, Fumio Watari

  CARBON 49 (7) 2287 - 2299 0008-6223 2011/06 [Refereed][Not invited]
   

  Induced pluripotent stem (iPS) cells have attracted worldwide interest. However, there have been only a few studies investigating effective culture substrates for feeder-free culturing for the maintenance of iPS cells. In this study, we cultured mouse iPS cells under feeder-free conditions on carbon nanotube (CNT)-coated dishes and then evaluated the colony morphology and differentiation state of the cells on the dishes. After 5 d of cultivation in a medium containing 15% fetal bovine serum (FBS) and leukemia inhibitory factor (LIF), the colonies on thick films of multi-walled CNTs (MWCNTs) were observed to be hemiround; further, the cells expressed early undifferentiation markers. On the other hand, the colonies on a cell culture polystyrene dish and a collagen-coated polystyrene dish showed indistinct outline and spread well, and most spreading cells only weakly expressed early undifferentiation markers. These results indicate that the thick films of MWCNTs could maintain hemiround colonies and undifferentiated state of mouse iPS cells cultured under feeder-free conditions. (C) 2011 Elsevier Ltd. All rights reserved.
• Toxicity evaluations of various carbon nanomaterials

  Motohiro Uo, Tsukasa Akasaka, Fumio Watari, Yoshinori Sato, Kazuyuki Tohji

  DENTAL MATERIALS JOURNAL 30 (3) 245 - 263 0287-4547 2011/05 [Refereed][Not invited]
   

  After the discovery of fullerene and carbon nanotubes, various carbon nanomaterials were discovered or synthesized. The carbon nanomaterials have remarkable properties, different from bulk materials with the same chemical composition, and are therefore useful for industrial applications. However, the toxicity of nanomaterials may also differ from that of the bulk materials; this difference poses a concern. The physical similarity of nanomaterials to asbestos has led to evaluations for toxicity by many researchers using various methods. In this review, we compile and compare the toxicity evaluations of each carbon nanomaterial.
• Observation of a 3D network nano-structure of carbon nanotubes scaffold for cultivation

  Shigeaki Abe, Kosuke Ishikawa, Atsushi Hyono, Hirohisa Kobayashi, Takayuki Kiba, Tsukasa Akasaka, Motohiro Uo, Yasutaka Yawaka, Shin-Ichiro Sato, Tetsu Yonezawa, Fumio Watari

  e-Journal of Surface Science and Nanotechnology 9 80 - 84 1348-0391 2011/03/05 [Refereed][Not invited]
   

  Development of scaffolds consisting of micro-/nano-sized materials have attracted a great deal of attention for their potential use in tissue engineering tools. We prepared a cell culture scaffold of carbon nanotubes, which is a typical bio-inert nanomaterial, and then investigated the surface morphology and properties. A three-dimensional nano-level network structure was observed using a scanning electron microscope and an atomic force microscope. The scaffold also exhibited excellent protein absorption. In order to apply the obtained scaffold to the cultivation of osteoblast cells, the cytocompatibility was comparable to that of a conventional cell culture dish. © 2011 The Surface Science Society of Japan.
• Observation of Internal Distribution Behavior of Micro/Nano-Sized Ceramics and Metal Particles in Mice

  Shigeaki Abe, Nobuki Iwadera, Mami Mutoh, Chika Koyama, Mitsue Esaki, Tsukasa Akasaka, Motohiro Uo, Manabu Morita, Yoshinori Kuboki, Koichi Haneda, Yasutaka Yawaka, Fumio Uchida, Tetsu Yonezawa, Fumio Watari

  Bioceramics Development and Applications 1 D110134  2011/01 [Refereed][Not invited]
  
• Development of a novel transparent substrate coated by carbon nanotubes through covalent bonding

  Shigeaki Abe, Katsutoshi Nakayama, Daisuke Hayashi, Tsukasa Akasaka, Motohiro Uo, Fumio Watari, Tomoya Takada

  9TH INTERNATIONAL CONFERENCE ON NANO-MOLECULAR ELECTRONICS 14 147 - 151 1875-3892 2011 [Refereed][Not invited]
   

  There is considerable investigation into the applications of carbon nanotubes because of their valuable properties. In this study, we succeeded in poly-carboxylation of multi-walled carbon nanotubes (CNTs) tethered to a glass substrate through covalent bonding. By causing a carboxylation reaction using a peroxide derivative, we were able to observe many carboxyl groups on the surfaces of CNTs. We characterized the obtained CNTs derivatives using Infrared and Raman spectroscopy. The CNTs reacted directly with glass substrates that presented amino groups, and the tethered CNTs were not removed from the substrate by sonication, suggesting the formation of a strong bond between the CNTs and substrate. Nanostructures in the shape of curled individual strings were observed using a scanning electron microscope and an atomic force microscope. The transparency of substrates was more than 97% in visible regions. (C) 2010 Published by Elsevier B.V.
• Internal distribution of micro- / Nano-sized inorganic particles and their cytocompatibility

  Shigeaki Abe, Nobuki Iwadera, Mitsue Esaki, Ikuhiro Kida, Mami Mutoh, Tsukasa Akasaka, Motohiro Uo, Yasutaka Yawaka, Manabu Morita, Koichi Haneda, Tetsu Yonezawa, Fumio Watari

  IOP Conference Series: Materials Science and Engineering 18 (13) 192013  1757-8981 2011 [Refereed][Not invited]
   

  Nano-sized materials have received much attention lately, both in terms of their multiple applications and their biocompatibility. From both viewpoints, understanding the biodistribution of administered nano-materials is very important. In this study, we succeeded in visualizing the biodistribution of administered nano-materials using a scanning X-ray analytical microscope and magnetic resonance imaging method. Quantitative observation was carried out by inductively coupled plasma - atomic emission spectroscopy. We observed that the administered nano-particles accumulated in the liver, lung and spleen of mice. To estimate their cytocompatibility, the nano-particles were exposed to human liver cells. The results suggested that the micro-/ nano- particles have good cytocompatibility, except for copper oxide nano-particles. © 2011 Ceramic Society of Japan.
• Application of Imogolite, Almino-Silicate Nanotube, as Scaffold for the Mineralization of Osteoblasts

  Kosuke Ishikawa, Tsukasa Akasaka, Shigeaki Abe, Yasutaka Yawaka, Masaya Suzuki, Fumio Watari

  Bioceramics Development and Applications 1 D110133  2011/01 [Refereed][Not invited]
  
• Culture of ES Cells and Mesenchymal Stem Cells on Carbon Nanotube Scaffolds

  Hiromi KITAHARA, Yoshinori KUBOKI, Hiroko TAKITA, Tsukasa AKASAKA, Fumio WATARI, Nobuo INOUE

  Nano Biomedicine ナノ・バイオメディカル学会 2 (2) 81 - 92 2010/12 [Refereed][Not invited]
   

  Cell proliferations on carbon nanotube scaffolds were investigated for the embryonic stem cells (ES cells) of mouse and the bone marrow-derived mesenchymal stem cells (MSC) of rat. Although ES cells were well attached and proliferated on gelatin-coated plastic dishes, they did not attach on the CNT-coated scaffold, and formed the spheroids growing in the culture medium. For MSC, they attached on the CNT-coated scaffold and grew to form mineralized particles as on the plastic dishes of control. The growth rate of the MSC was lower than control but showed the higher expression of alkaline phosphatase activity per cell in 2 weeks and degree of mineralization per cell for 3 and 4 weeks.
• Strong adhesion of Saos-2 cells to multi-walled carbon nanotubes

  Makoto Matsuoka, Tsukasa Akasaka, Yasunori Totsuka, Fumio Watari

  MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 173 (1-3) 182 - 186 0921-5107 2010/10 [Refereed][Not invited]
   

  In recent years, carbon nanotubes (CNTs) have been considered potential biomedical materials because of their unique character. The aim of this study was to investigate the response of a human osteoblast-like cell line - Saos-2 - on single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs). The surface of a culture dish was coated with CNTs, and Saos-2 cells were cultured for three days. Cell morphology, viability, alkaline phosphatase (ALP) activity, adhesion, and vinculin expression were evaluated. The result showed high cell viability and strong adhesion to MWCNTs. Saos-2 cultured on MWCNTs exhibited vinculin expression throughout the cell body. while the cells attached to SWCNTs and glass were mostly limited to their periphery. Our results suggest that CNT coatings promote cell activity and adhesiveness. These findings indicate that MWCNTs could be used as surface coating materials to promote cell adhesion. (C) 2009 Elsevier B.V. All rights reserved.
• The bactericidal effect of carbon nanotube/agar composites irradiated with near-infrared light on Streptococcus mutans

  Tsukasa Akasaka, Makoto Matsuoka, Takeshi Hashimoto, Shigeaki Abe, Motohiro Uo, Fumio Watari

  MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS 173 (1-3) 187 - 190 0921-5107 2010/10 [Refereed][Not invited]
   

  Dental caries are mainly associated with oral pathogens, and Streptococcus mutans is a primary cariogenic organism. Many methods have been established to eliminate S. mutans from the oral cavity. This study aimed to evaluate the effect of carbon nanotube (CNT)/agar composites irradiated with near-infrared (NIR) light on S. mutans, as a potential photothermal antimicrobial nanotherapy. A colony-forming unit assay clearly showed that CNT/agar composites attain bactericidal activity after NIR light irradiation; this bactericidal activity is higher than that of graphite (GP)/agar and activated carbon (AC)/agar composites. Furthermore, it was observed that longer irradiation times immobilized S. mutans in the CNT/agar composite. (C) 2010 Elsevier B.V. All rights reserved.
• Photophysical characterization of cumarin-doped poly (lactic acid) microparticles and visualization of the biodistribution

  Shigeaki Abe, Takayuki Kiba, Kiyotada Hosokawa, Satoru Nitobe, Takashi Hirota, Hirohisa Kobayashi, Tsukasa Akasaka, Motohiro Uo, Yoshinori Kuboki, Shin-Ichiro Sato, Fumio Watari, Iosif D. Rosca

  JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 181 (2-3) 181 - 185 0368-2048 2010/08 [Refereed][Not invited]
   

  We prepared fluorescent coumarin dye-doped poly (acrylic acid) microparticles, which are well known as a biodegradable polyester, and the photophysical properties were characterized by scanning electron microscope, atomic force microscope and spectroscopic investigation. Spherical particles with diameters ranging from 0.5 to a few mu m were obtained. Based on spectroscopic investigation, the internal environment was close to that of a polar solvent such as methanol, and the dyes were dispersed without aggregation inside the particles. The obtained particles were administered to a mouse through the tail vein, and the biodistribution was then observed after some organs were excited at 1-day and 1-week post-injection. The particles were accumulated ill the organs, especially in the lung and spleen. After injection, the particles were trapped temporally in the lung, and then seemed to be transported to other organs by blood circulation. This tendency is similar to the biodistribution of TiO(2) microparticles that we have reported previously. (C) 2010 Elsevier B.V. All Fights reserved.
• Chromatography of carbon nanotubes separated albumin from other serum proteins: a method for direct analysis of their interactions

  Yoshinori Kuboki, Takamitu Koshikawa, Hiroko Takita, Ryuichi Fujisawa, Min-ho Lee, Shigeaki Abe, Tsukasa Akasaka, Motohiro Uo, Fumio Watari, Rachel Sammons

  DENTAL MATERIALS JOURNAL 29 (4) 369 - 373 0287-4547 2010/07 [Refereed][Not invited]
   

  Chromatography technology was employed to clarify the mechanism of interaction between multi-wall carbon nanotubes (MWCNT) and proteins. A column (16x100 mm) was packed with purified MWCNT, and various proteins were eluted with phosphate buffered saline (PBS) with and without gradient systems. It was found that albumin in bovine serum was eluted immediately from the column without any adsorption to MWCNT. Conversely, the non-albumin proteins, including a protein of 85 kDa molecular mass and a group of proteins with molecular masses higher than 115 kDa, exhibited considerably high affinity towards MWCNT. A sample of pure bovine serum albumin was also eluted immediately from the column, while lysozyme did not elute as a peak with PBS, but eluted with 0.6 M NaCl. Fundamentally, carbon nanotubes are devoid of any electrical charge. Therefore, other forces including the hydrogen bonds, hydrophilic interactions, and van der Waals forces were most probably responsible for the differential elution behaviors. In conclusion, this chromatographic method provided a simple and direct analysis of the interactions between carbon nanotubes and the various proteins.
• Internal distribution of micro-/nano-sized ceramics and metals particles in mice

  Shigeaki Abe, Ikuhiro Kida, Mitsue Esaki, Nobuki Iwadera, Mami Mutoh, Chika Koyama, Tsukasa Akasaka, Motohiro Uo, Yoshinori Kuboki, Manabu Morita, Yoshinori Sato, Koichi Haneda, Tetsu Yonezawa, Balachandran Jeyadevan, Kazuyuki Tohji, Fumio Watari

  JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 118 (1378) 525 - 529 1882-0743 2010/06 [Refereed][Not invited]
   

  Internal distribution of several nanoparticles in mice has been investigated using scanning X-ray analytical microscopy, magnetic resonance imaging and inductively coupled plasma atomic emission spectroscopy. According dynamic laser scattering analysis, the actual particle size of obtained metal oxide was similar to that of metal particles. The estimated diameters were ca. one micrometer. After administration through the tail vein of the mice, metal particles quickly reached some organs. The distribution ratio reached a constant value and was then maintained. On the other hand, the metal oxide particles were first localized in the spleen and lung. The concentration in the lung was decreased with post-injection time. This result suggested that the particles were temporally trapped in the lung then removed to other organs. The behaviors between metal and metal oxide were quite different even when those particles had a similar actual particle size. Therefore, the distribution behavior of particles depended on the chemical species. (C) 2010 The Ceramic Society of Japan All rights reserved.
• In Vitro Study of Cell Differentiation by Mouse Embryo Stem Cells on Nanocarbon Tubes

  Koichi IMAI, Kazuhiko SUESE, Tsukasa AKASAKA, Fumio WATARI, Shoji TAKEDA

  Nano Biomedicine ナノ・バイオメディカル学会 2 (1) 47 - 51 2010/06 [Refereed][Not invited]
   

  We examined the influence of culture methods with mono- and multilayer nanocarbon tubes (SWCNT and MWCNT, respectively) on the differentiation of mouse embryonic stem (ES) cells using a cellular differentiation technique for the embryonic stem cell test (EST). On differentiation assay, beating was noted in 72, 35, and 60% of the cells in the control, SWCNT, and MWCNT groups, respectively. In addition, there was no influence on cytotoxicity based on the LDH level. In this study, the MWCNT did not influence the differentiation of ES cells, but the SWCNT markedly inhibited it, confirming that the differentiation of ES cells depends on the material surface structure.
• 3D collagen scaffolds coated with multiwalled carbon nanotubes: Initial cell attachment to internal surface

  Eri Hirata, Motohiro Uo, Yoshinobu Nodasaka, Hiroko Takita, Natsumi Ushijima, Tsukasa Akasaka, Fumio Watari, Atsuro Yokoyama

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS 93B (2) 544 - 550 1552-4973 2010/05 [Refereed][Not invited]
   

  The cell adhesion in a multiwalled carbon nanotube-coated collagen sponge (MWCNT-coated sponge) was investigated Immediately after seeding, the cells adhered to the inner surface of the MWCNT-coated sponge and a significantly larger number of cells were observed there than for a pure collagen sponge used as control On the MWCNT-coated sponge, the cells appeared favorable adhesion and spread in the early stages in the center part of the sponge which cells rarely attached without MWCNT-coating It was suggested that the physical structure of MWCNTs was effective for initial adhesion of cells from the result of serum-free culture MWCNT-coating makes the material a suitable three-dimensional scaffold for cell culturing, as opposed to other scaffold systems where such an effect is not seen (C) 2010 Wiley Periodicals, Inc J Biomed Mater Res Part B Appl Biomater 93B 544-550, 2010
• Thin films of single-walled carbon nanotubes promote human osteoblastic cells (Saos-2) proliferation in low serum concentrations

  Tsukasa Akasaka, Atsuro Yokoyama, Makoto Matsuoka, Takeshi Hashimoto, Fumio Watari

  MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 30 (3) 391 - 399 0928-4931 2010/04 [Refereed][Not invited]
   

  One strategy used for the regeneration of bone is the development of cell culture substrates and scaffolds that can control osteoblast proliferation and differentiation. In recent investigations, carbon nanotubes (CNTs) have been utilized as scaffolds for osteoblastic cell cultures; however, there are only a few reports describing the proliferation of osteoblastic cells on thin CNT films; in particular, the effects of serum concentration on cell proliferation have not been studied. In the present study, we prepared culture dishes with homogeneous thin or thick films of non-modified CNTs and examined the effect of serum concentrations on human osteoblastic cells (Saos-2) proliferation in these culture dishes. We demonstrated that the ratio of cell proliferation was strongly affected by the concentration of serum. Interestingly, single-walled carbon nanotube (SWNT) thin films were found to be the most effective substrate for the proliferation of Saos-2 cells in low concentrations of serum. Thus, thin SWNT films may be used as an effective biomaterial for the culture of Saos-2 cells in low serum concentrations. (C) 2009 Elsevier B.V. All rights reserved.
• High Functional Expression of Osteoblasts on Imogolite, Aluminosilicate Nanotubes

  Kosuke Ishikawa, Tsukasa Akasaka, Yasutaka Yawaka, Fumio Watari

  JOURNAL OF BIOMEDICAL NANOTECHNOLOGY 6 (1) 59 - 65 1550-7033 2010/02 [Refereed][Not invited]
   

  Imogolite is a naturally occurring aluminosilicate clay mineral with a nanotube structure of 2 nm diameter and 60 nm-2 mu m length. In this study, synthetic imogolite nanotubes were applied to cell culture and the properties as a scaffold were compared with those of a conventional culture dish and a carbon nanotube (CNT) scaffold. The surface characteristics of the imogolite scaffold were drastically changed with the amount of coated imogolite on the dish. With the increase of imogolite concentration, the surface morphology of the scaffolds changed from an island-like shape in random orientation to a self-organized fiber texture aligned in the same direction, and finally full coverage in a random orientation with plural layers. Silicon releasability of the scaffolds was increased with the amount of coated imogolite. Mouse osteoblast-like cells (MC3T3-E1) cultured on imogolite showed a flat-form morphology and a cytoskeleton developed in all directions in contrast to a spindle-shaped morphology developed in one direction on cell culture dishes and CNT scaffolds. The proliferation and osteoblastic functions in ALP activity and mineralization showed similar increasing tendency. The largest values were obtained from the scaffold with a high concentration of imogolite. The results indicated good biocompatibility between the cells and imogolite scaffold and the enhancement effect of proliferation and osteoblastic differentiation.
• Various nanotube scaffolds for cell proliferation

  F. Watari, T. Akasaka, K. Ishikawa, M. Matsuoka, E. Hirata, N. Terada, A. Yokoyama, M. Uo, S. Itoh, Y. Yawaka, M. Suzuki, N. Takashi, Y. Totsuka, Y. Kitagawa, S. Abe, I. D. Rosca, Y. Kuboki, Y. Bando

  MULTISCALE, MULTIFUNCTIONAL AND FUNCTIONALLY GRADED MATERIALS 631-632 181 - + 0255-5476 2010 [Refereed][Not invited]
   

  Carbon nanotubes (CNT) and their derivatives with different structure and compositions have unique features. In the present study, cell proliferation was performed on various nanotubes such as single walled CNTs, multiwalled CNTs and imogolite which is nanotubes of aluminosilicate. SEM observation of the growth of osteoblast-like cells cultured on CNTs showed the morphology fully developed for the whole direction, which was different from that extended to the one direction on the usual scaffold. Numerous filopodia were grown from cell edge, extended far long and combined with CNT meshwork. Apatite precipitation in simulated body fluid, affinity for proteins and saccharides, and nanosize meshwork structure with large porosity would be the properties responsible for these cell adhesion and growth. Imogolite showed the similar properties to CNTs. Nanotubes could be the favorable materials for biomedical applications.
• Preparation and Properties of Thermoplastic-resin-based Nanocomposites for the Development of Esthetic Orthodontic Wires

  Shuichi YAMAGATA, Tsukasa AKASAKA, Motohiro UO, Natsumi USHIJIMA, Yoshinobu NODASAKA, Junichiro IIDA, Fumio WATARI

  Nano Biomedicine 1 (2) 151 - 158 2009/12 [Refereed][Not invited]
  
• Physical Properties of Aluminosilicate Nanotubes, Imogolite, as Scaffold and Effect on Osteoblastic Mineralization

  Kosuke ISHIKAWA, Tsukasa AKASAKA, Yoshinobu NODASAKA, Natsumi USHIJIMA, Masayuki KAGA, Shigeaki ABE, Motohiro UO, Yasutaka YAWAKA, Masaya SUZUKI, Fumio WATARI

  Nano Biomedicine 1 (2) 109 - 120 2009/12 [Refereed][Not invited]
  
• Synthesis and Characterization of a Water-soluble Multi-walled Carbon Nanotube and Its Biodistribution in Mice

  Shigeaki ABE, Daisuke HAYASHI, Tsukasa AkASAKA, Motohiro UO, Yoshinori KUBOKI, Fumio WATARI, Tomoya TAKADA

  Nano Biomedicine 1 (2) 143 - 150 2009/12 [Refereed][Not invited]
  
• Effect of carbon nanotubes on cellular functions in vitro

  Xiaoming Li, Hong Gao, Motohiro Uo, Yoshinori Sato, Tsukasa Akasaka, Qingling Feng, Fuzhai Cui, Xinhui Liu, Fumio Watari

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A 91A (1) 132 - 139 1549-3296 2009/10 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) have been shown to affect cell behavior. But how and why the CNTs affect potential differentiation of the attached cells has not been largely known. In this study, multiwalled carbon nanotubes (MWNTs) and graphite (GP) were pressed as compacts. Higher ability of CNTs to adsorb proteins, compared with GP, was shown. Myoblastic mouse cells (C2C12) were cultured and the cell responses to the two kinds of compacts were compared in vitro. Meanwhile, we used cell culture on the culture plate as a control. During the conventional culture, significantly better cell attachment, proliferation, and differentiation of cells on the MWNTs were found. To confirm the hypothesis that the larger amount of protein adsorbed on the CNTs was crucial for this, we made the compacts adsorb more proteins in culture medium with 50% fetal bovine serum (FBS) before cell culture. With the adsorption of the proteins in advance, the increments of the total-protein/DNA and alkaline phosphatase (ALP)/DNA for the MWNTs was respectively as about 11 times and 18 times as the increments of those for GP and the control at both day 4 and day 7. Therefore, the CNTs might induce cellular functions by adsorbing more proteins, which indicated that the CNTs might be a candidate for scaffold material for tissue engineering. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 91A: 132-139, 2009
• Time-Dependence and Visualization of TiO(2) and Pt Particle Biodistribution in Mice

  Shigeaki Abe, Chika Koyama, Motohiro Uo, Tsukasa Akasaka, Yoshinobu Kuboki, Fumio Watari

  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 9 (8) 4988 - 4991 1533-4880 2009/08 [Refereed][Not invited]
   

  Micro- and nano-sized materials have received much attention regarding their biocompatibility and toxicity. To understand the influence of such materials on animals, it is very important to determine their internal distribution behavior. In this study, the biodistributions of Pt and TiO(2) micro- and nano-sized particles in mice were estimated and visualized by X-ray scanning analytical microscopy and inductively coupled plasma-atomic emission spectroscopy. We also determined the effect of particle size, difference between metal and oxide, and time dependence for the distributions, because the biodistribution depends upon both the chemical character of materials and the size of particles. The results of the present study indicated that the difference in chemical character had a greater effect than did particle size. We predict that X-ray scanning analytical microscopy will be a useful method for studying biodistribution of micro- and nano-sized particles, because this method requires no labeling or treatment of the target particles.
• In Vitro Evaluation of Porous Poly(L-Lactic Acid) Scaffold Reinforced by Chitin Fibers

  Xiaoming Li, Xinhui Liu, Wei Dong, Qingling Feng, Fuzhai Cui, Motohiro Uo, Tsukasa Akasaka, Fumio Watari

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS 90B (2) 503 - 509 1552-4973 2009/08 [Refereed][Not invited]
   

  In this study, the previously reported porous three-dimensional poly(L-lactic acid) (PLLA) scaffolds reinforced by the chitin fibers (PLLA/CF) with and without the link were evaluated in vitro. Firstly, pH value of the phosphate buffered saline lixiviums of the PLLA/CF with different content of the chitin fibers was measured to get an appropriate content of the chitin fibers in the PLLA/CF. Then, the cell functions (attachment, proliferation, alkaline phosphatase per unit cell, total protein per unit cell, and osteonectin, osteopontin, and osteocalcin gene expression) of human osteoblast-like cells (SaOS2) cultured on the PLLA/CF with the link, PLLA/CF without the link and PLLA scaffold were compared. The results showed that the link treatment did not significantly influence the pH value of the lixiviums of the scaffolds, 30% volume content might be an appropriate content of the chitin fibers in PLLA/CF scaffold to keep the pH value of the lixiviums of the scaffolds between 7.0 and 7.2 during the lixiviation time of 16 weeks, the PLLA/CF scaffold was significantly better for the attachment, proliferation, differentiation, and mineralization of the osteoblast than PLLA, the link treatment did not significantly influence these cells activities, which further suggested that PLLA/CF with the link treatment might be an appropriate scaffold for tissue engineering. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 90B: 503-509, 2009
• Development of a 3D Collagen Scaffold Coated With Multiwalled Carbon Nanotubes

  Eri Hirata, Motohiro Uo, Hiroko Takita, Tsukasa Akasaka, Fumio Watari, Atsuro Yokoyama

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS 90B (2) 629 - 634 1552-4973 2009/08 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) have attractive biochemical properties such as strong cell adhesion and protein absorption, which are very useful for a cell cultivation scaffold. In this study, We prepared a multiwalled carbon nanotube-coated collagen sponge (MWCNT-coated sponge) to improve the surface properties of the collagen sponge, and its cell culturing properties Were examined. The suface of the collagen sponge was homogeneously coated with MWCNTs by dispersion. MC3T3-E1 cells were cultured on and inside the MWCNT-coated sponge. The DNA content on the MWCNT-coated sponge after 1 week of culture was significantly higher than on an uncoated collagen sponge (p < 0.05). There was no significant difference between the estimated ALP activity normalized by DNA quantity on the MWCNT-coated sponge and that on the uncoated collagen sponge which is well known as one of the best scaffolds for cell cultivation. In addition, the MWCNT-coated surface shows strong cell adhesion. Therefore, the MWCNT-coated collagen sponge is expected to be a useful 3D scaffold for cell cultivation. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 90B: 629-634, 2009
• Proliferation of osteoblast cells on nanotubes

  F. Watari, T. Akasaka, Xiaoming Li, M. Uo, A. Yokoyama

  Frontiers of Materials Science in China 3 (2) 169 - 173 1673-7377 2009/06 [Refereed][Not invited]
   

  Carbon nanotubes (CNT) have a unique structure and feature. In the present study, cell proliferation was performed on the scaffolds of single-walled CNTs (SWCNT), multiwalled CNTs (MWCNT), and on graphite, one of the representative isomorphs of pure carbon, for the sake of comparison. Scanning electron microscopy observation of the growth of osteoblast-like cells (Saos2) cultured on CNTs showed the morphology fully developed for the whole direction, which is different from that extended to one direction on the usual scaffold. Numerous filopodia were grown from cell edge, extended far long and combined with the CNT meshwork. CNTs showed the affinity for collagen and proteins. Proliferated cell numbers are largest on SWCNTs, followed by MWCNTs, and are very low on graphite. This is in good agreement with the sequence in the results of the adsorbed amount of proteins and expression of alkaline phosphatase activity for these scaffolds. The adsorption of proteins would be one of the most influential factors to make a contrast difference in cell attachment and proliferation between graphite and CNTs, both of which are isomorphs of carbon and composed of similar graphene sheet crystal structure. In addition, the nanosize meshwork structure with large porosity is another property responsible for the excellent cell adhesion and growth on CNTs. CNTs could be the favorable materials for biomedical applications. © 2009 Higher Education Press and Springer-Verlag GmbH.
• Observation of Biodistribution of Indium-Tin Oxide Nanoparticles in Mice

  Shigeaki ABE, Tetsu YONEZAWA, Tsukasa AKASAKA, Motohiro UO, Fumio UCHIDA, Fumio WATARI

  Nano Biomedicine 1 (1) 70 - 74 2009/06 [Refereed][Not invited]
  
• Material nanosizing effect on living organisms: non-specific, biointeractive, physical size effects

  Fumio Watari, Noriyuki Takashi, Atsuro Yokoyama, Motohiro Uo, Tsukasa Akasaka, Yoshinori Sato, Shigeaki Abe, Yasunori Totsuka, Kazuyuki Tohji

  JOURNAL OF THE ROYAL SOCIETY INTERFACE 6 (3) S371 - S388 1742-5689 2009/06 [Refereed][Not invited]
   

  Nanosizing effects of materials on biological organisms was investigated by biochemical cell functional tests, cell proliferation and animal implantation testing. The increase in specific surface area causes the enhancement of ionic dissolution and serious toxicity for soluble, stimulative materials. This effect originates solely from materials and enhances the same functions as those in a macroscopic size as a catalyst. There are other effects that become prominent, especially for non-soluble, biocompatible materials such as Ti. Particle size dependence showed the critical size for the transition of behaviour is at approximately 100 mm, 10 mm and 200 nm. This effect has its origin in the biological interaction process between both particles and cells/tissue. Expression of superoxide anions, cytokines tumour necrosis factor-alpha and interleukin-1 beta from neutrophils was increased with the decrease in particle size and especially pronounced below 10 mm, inducing phagocytosis to cells and inflammation of tissue, although inductively coupled plasma chemical analysis showed no dissolution from Ti particles. Below 200 nm, stimulus decreases, then particles invade into the internal body through the respiratory or digestive systems and diffuse inside the body. Although macroscopic hydroxyapatite, which exhibits excellent osteoconductivity, is not replaced with natural bone, nanoapatite composites induce both phagocytosis of composites by osteoclasts and new bone formation by osteoblasts when implanted in bone defects. The progress of this bioreaction results in the conversion of functions to bone substitution. Although macroscopic graphite is non-cell adhesive, carbon nanotubes (CNTs) are cell adhesive. The adsorption of proteins and nano-meshwork structure contribute to the excellent cell adhesion and growth on CNTs. Non-actuation of the immune system except for a few innate immunity processes gives the non-specific nature to the particle bioreaction and restricts reaction to the size-sensitive phagocytosis. Materials larger than cell size, approximately 10 mm, behave inertly, but those smaller become biointeractive and induce the intrinsic functions of living organisms. This bioreaction process causes the conversion of functions such as from biocompatibility to stimulus in Ti-abraded particles, from non-bone substitutional to bone substitutional in nanoapatite and from non-cell adhesive to cell adhesive CNTs. The insensitive nature permits nanoparticles that are less than 200 nm to slip through body defence systems and invade directly into the internal body.
• Maturation of osteoblast-like SaoS2 induced by carbon nanotubes

  Xiaoming Li, Hong Gao, Motohiro Uo, Yoshinori Sato, Tsukasa Akasaka, Shigeaki Abe, Qingling Feng, Fuzhai Cui, Fumio Watari

  BIOMEDICAL MATERIALS 4 (1) 015995  1748-6041 2009/02 [Refereed][Not invited]
   

  Osteogenic maturation of the osteoblast is crucial for bone formation. In this study, multi-walled carbon nanotubes (MWCNTs) and graphite (GP) were pressed as compacts. The greater ability of carbon nanotubes to adsorb proteins, compared with graphite, was shown. Human osteoblast-like SaoS2 cells were cultured and the cell response to the two kinds of compacts was compared in vitro. Meanwhile, we used cell culture on the culture plate as a control. Assays for osteonectin, osteopontin and osteocalcin gene expression, total protein (TP) amount, alkaline phosphatase activity (ALP) and DNA of cells cultured on the samples were done. During the conventional culture, significantly higher osteonectin, osteopontin and osteocalcin gene expression level, ALP/DNA and TP/DNA on carbon nanotubes were found. To confirm the hypothesis that the larger amount of specific proteins adsorbed on the carbon nanotubes was crucial for this, the compacts were pre-soaked in culture medium having additional recombinant human bone morphogenetic protein-2 (rhBMP-2) before cell culture. Compared with GP, osteonectin, osteopontin and osteocalcin gene expression level, ALP/DNA and TP/DNA of the cells tested increased more on the MWCNTs after the compacts were pre-soaked in the culture medium with rhBMP-2. The results indicated that the carbon nanotubes might induce osteogenic maturation of the osteoblast by adsorbing more specific proteins.
• Capture of bacteria by flexible carbon nanotubes

  Tsukasa Akasaka, Fumio Watari

  ACTA BIOMATERIALIA 5 (2) 607 - 612 1742-7061 2009/02 [Refereed][Not invited]
   

  Capture of bacteria with flexible carbon nanotubes (CNTs) was done in vitro. Bundles of single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) was mixed with Streptococcus mutans. Precipitation assays and colony-forming unit formation assays showed free S. mutans in the solution was significantly decreased by the addition of the CNTs. Observation of the precipitate by scanning electron microscopy showed bacterial adhesion to CNTs. It has been shown that CNTs of different diameters have significantly different effects on the precipitation efficiency, and the manners in which they capture the cells are different. We found that MWCNTs (diameter of approximately 30 nm) had the highest precipitation efficiency, which was attributable to both their adequate dispersibility and aggregation activity. From observations by scanning electron microscopy, bundles of SWCNTs and thin MWCNTs (diameter of approximately 30 nm), which were moderately flexible, were easily wound around the curved surface of S. mutans. Bare CNTs having high adhesive ability could be useful as biomaterials, e.g., as tools for the elimination of oral pathogens at the nano-level. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
• Adhesion of human osteoblast-like cells (Saos-2) to carbon nanotube sheets

  Tsukasa Akasaka, Atsuro Yokoyama, Makoto Matsuoka, Takeshi Hashimoto, Shigeaki Abe, Motohiro Uo, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (2-3) 147 - 153 0959-2989 2009 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) exhibit excellent cell proliferation properties, which can serve as a scaffold for cell culturing. However, there are only a few reports on adhesion of osteoblast-like cells to a CNT sheet. In this study, we investigated adhesion of osteoblast-like cells to single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) sheets and compared these adhesions with that on a cell culture polystyrene dish by using a cell adhesion test and a scanning electron microscope. The MWNT sheets exhibited faster adhesion of cells at an initial stage than SWNT sheets and cell culture polystyrene dish. The number of attached cells on the MWNT sheets seemed to be greater than on SWNT sheets and cell culture polystyrene. Moreover, the MWNT sheets exhibited both high speed and good capacity for cell adhesion. However, the surface of the MWNT sheets was such that it facilitated cell adherence but hindered the spreading of the attached cells. Interestingly, cell adhesion to CNT sheets was significantly influenced by pre-coating with serum. These results indicate that CNT sheets would play an important role in adsorption of serum proteins, which would consequently facilitate cell adhesion, and that the MWNT sheets have a high cell adhesiveness.
• Improvement in cell proliferation on silicone rubber by carbon nanotube coating

  Makoto Matsuoka, Tsukasa Akasaka, Takeshi Hashimoto, Yasunori Totsuka, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (2-3) 155 - 162 0959-2989 2009 [Refereed][Not invited]
   

  Silicone rubbers are widely used as tissue implants because of their flexibility and chemical stability. However, they have limited cellular adhesiveness and may cause problems in the long term. In this study, a coating of carbon nanotubes (CNTs) was applied to silicone rubber to improve its cellular adhesiveness. Scanning electron micrograph of this coating revealed that CNTs had formed a densely packed meshwork; the R-a values and protein adsorption capacity were enhanced. Although the contact angle did not change after coating, it decreased after immersion into a culture medium. After cultivation for 6 d, while Saos-2 cells were hardly observed on untreated silicone, the cells proliferated on CNT-coated silicone. Thus, CNT coating might be a simple and effective solution to problems associated with silicone implants.
• Modification of the dentin surface by using carbon nanotubes

  Tsukasa Akasaka, Keiko Nakata, Motohiro Uo, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (2-3) 179 - 185 0959-2989 2009 [Refereed][Not invited]
   

  Recent studies have shown that carbon nanotubes (CNTs) can be used as biomedical materials because of their unique properties. CNTs effect nucleation of hydroxyapatite, because of which considerable interest has been generated regarding the use of CNTs in dentistry. However, there are only a few reports on the use of CNTs as dental materials. In this study, we investigated the changes induced in the surfaces of tooth slices by the application of a coating of CNTs by observing CNT-coated tooth slices both macroscopically as well as under a scanning electron microscope. Further, we investigated the effect of CNT coating on the tensile bond strength of dentin adhesives. CNTs adhered easily to the tooth surfaces when tooth slices were suspended in a CNT-dispersed solution. Interestingly, it was observed that CNTs selectively adhered to the surfaces of dentin and cementum, possibly by adhering to their exposed collagen fibers. In addition, the CNT coating did not affect the tensile bond strength of dentin adhesives. These results indicate that coating of the teeth with CNTs can be a possible application of CNTs as dental materials.
• Visualization of invasion into the body and internal diffusion of nanoparticles

  F. Watari, S. Abe, I. D. Rosca, A. Yokoyama, M. Uo, T. Akasaka, N. Takashi, Y. Totsuka, E. Hirata, M. Matsuoka, K. Ishikawa, S. Itoh, Y. Yawaka

  BIOCERAMICS 21 396-398 569 - 572 1013-9826 2009 [Refereed][Not invited]
   

  Nanoparticles may invade directly into the internal body through the respiratory or digestive system and diffuse inside body. The behavior of nanoparticles in the internal body is also essential to comprehend for the realization of DDS. Thus it is necessary to reveal the internal dynamics for the proper treatments and biomedical applications of nanoparticles. In the present study the plural methods with different principles such as X-ray scanning analytical microscope (XSAM), MRI and Fluorescent microscopy were applied to enable the observation of the internal diffusion of micro/nanoparticles in the (1) whole body level, (2) inner organ level and (3) tissue and intracellular level. Chemical analysis was also done by ICP-AES for organs and compared with the results of XSAM mapping.
• Multiwalled carbon nanotube monoliths prepared by spark plasma sintering (SPS) and their mechanical properties

  Motohiro Uo, Tomoka Hasegawa, Tsukasa Akasaka, Isao Tanaka, Fuminori Munekane, Mamoru Omori, Hisamichi Kimura, Reiko Nakatomi, Kohei Soga, Yasuo Kogo, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (1) 11 - 17 0959-2989 2009 [Refereed][Not invited]
   

  Three types of multiwalled carbon nanotube (MWCNT) monoliths without any binders were obtained by spark plasma sintering (SPS) treatment at 2000 degrees C under 80 MPa sintering pressure. Three MWCNTs with different diameters: thin (empty set20-30 nm, CNT Co., Ltd., Korea), thick (empty set100 nm, Nano Carbon Technologies Co., Ltd., Japan) and spherical thin (empty set20-30 nm, granulated diameter = 1-3 mu m, Shimizu Corporation, Japan) were employed for SPS. SEM observation confirmed that these materials maintained the nanosized tube microstructure of raw CNT powder after SPS treatment. The densest monolith was prepared with the spherical MWCNTs. The mechanical properties of this material were estimated by the dynamic hardness test. The elastic modulus of the monolith did not depend on the difference of MWCNTs, but the hardness of spherical MWCNTs was higher than that of thick MWCNTs. The high density and hardness of the spherical MWCNTs were caused by the high packing density during the SPS process because of its spherical granulation. Thus, the spherical MWCNTs were most useful for the MWCNT monolith preparation with the SPS process and its application as a bone substitute material and a bone tissue engineering scaffold material was suggested.
• Biodistribution imaging of magnetic particles in mice: X-ray scanning analytical microscopy and magnetic resonance imaging

  Shigeaki Abe, Ikuhiro Kida, Mitsue Esaki, Tsukasa Akasaka, Motohiro Uo, Toshiaki Hosono, Yoshinori Sato, Balachandran Jeyadevan, Yoshinori Kuboki, Manabu Morita, Kazuyuki Tohji, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (2-3) 213 - 220 0959-2989 2009 [Refereed][Not invited]
   

  Nano-sized particles have received much attention in view of their varied application in a wide range of fields. For example, magnetite (Fe(3)O(4)) nanoparticles have been investigated for various medical applications. In this study, we visualized the distribution of administered magnetic nanoparticles in mice using both X-ray scanning analytical microscopy (XSAM) and magnetic resonance imaging (MRI). After administration, the nanoparticles were rapidly dispersed via the blood circulation, and reached the liver, kidney and spleen. Using the XSAM and MRI methods in a complementary fashion, the biodistribution of nano-sized magnetite particles was successfully visualized.
• In vivo internal diffusion of several inorganic microparticles through oral administration

  Shigeaki Abe, Chila Koyama, Mitsue Esaki, Tsukasa Akasaka, Motohiro Uo, Yoshinori Kuboki, Manabu Morita, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (2-3) 221 - 229 0959-2989 2009 [Refereed][Not invited]
   

  We observed the internal diffusion behavior of inorganic micro/nano particles through oral administration. By oral exposure, the fed particles were absorbed through the digestive system then reached some organs after internal diffusion in the body. For example, TiO(2) particles fed to mice were detected in the lung, liver, and spleen after 10 days of feeding. Whereas, the absorption efficiency was extremely low compared with intravenous injection. In a comparison of the simple amount of administration, oral exposure required 10(2) times or more amount by intravenous injection for detection by an X-ray scanning analytical microscope. During dental treatment, micro/nano particles from tooth or dental materials would generate in the oral cavity, and some of the particles had a possibility to be swallowed, absorbed through the digestive system, and then diffuse into the body. However, our results suggest that biocompatible microparticles that are naturally taken orally affect animals only rarely because of the low absorption efficiency.
• Multiwalled carbon nanotube coating on titanium

  Michiko Terada, Shigeaki Abe, Tsukasa Akasaka, Motohiro Uo, Yoshimasa Kitagawa, Fumio Watari

  BIO-MEDICAL MATERIALS AND ENGINEERING 19 (1) 45 - 52 0959-2989 2009 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) have excellent chemical durability, mechanical strength and electrical properties. Therefore, there is interest in CNTs for not only electrical and mechanical applications, but also biological and medical applications. We coated titanium, a common material for dental implants, with multiwalled carbon nanotubes (MWCNTs). First, titanium was aminated and covered with collagen. Then, the carboxylated MWCNTs were coated onto the collagen attached to the titanium plate. The collagen-coated titanium plate had a homogeneous MWCNT coating, which showed strong attachment to the titanium surface as a thin layer. The surface roughness was significantly increased with the MWCNT coating. MC3T3-E1 cells were cultured on the MWCNT-coated Ti plate, and showed good cell proliferation and strong cell adhesion. Therefore, the MWCNT coating for titanium could be useful for improvement of cell adhesion on titanium implants.
• Development of a multiwalled carbon nanotube coated collagen dish

  Michiko Terada, Shigeaki Abe, Tsukasa Akasaka, Motohiro Uo, Yoshimasa Kitagawa, Fumio Watari

  Dental Materials Journal 28 (1) 82 - 88 0287-4547 2009 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) are one of the most interesting nanomaterials because of their excellent characteristics. In this study, a transparent CNTs coating for cell culture dishes was developed and its properties for cell culture were estimated. Carboxylated multiwalled carbon nanotubes (MWCNTs) were dispersed in aqueous sodium cholate solution and applied on a collagen type I-coated cell culture dish (cover glass). The dish surface was homogeneously covered by MWCNTs without aggregation. The MWCNT-coated dish was slightly gray and had good transparency, so conventional optical microscopic observation of the cells on the MWCNT-coated dish was possible. Rat osteoblast-like cells cultured on the MWCNT-coated dish showed slightly lower viability and proliferation compared to the collagen-coated dish. The cell adhesion on the MWCNT-coated dish was much higher than that on the collagen-coated dish. Therefore, MWCNT-coating for dishes will be a useful new material for cell culture.
• XAFS Analysis of Ti and Ni Dissolution from Pure Ti, Ni-Ti Alloy, and SUS304 in Soft Tissues

  Motohiro Uo, Kiyotaka Asakura, Kazuchika Tamura, Yasunori Totsuka, Shigeaki Abe, Tsukasa Akasaka, Fumio Watari

  CHEMISTRY LETTERS 37 (9) 958 - 959 0366-7022 2008/09 [Refereed][Not invited]
   

  Ti, a Ni-Ti alloy, and stainless steel (SUS304) were implanted in rat soft tissues for 6 months. The chemical states of the component elements contained in the tissues surrounding those metallic implants were analyzed by fluorescence X-ray absorption line structure (XAFS). Titanium oxide and a nickel aquo complex, which Would be Caused by the erosion of Ti and Ni, were detected in the Surrounding tissues. The concentrations of Ti and Ni in the tissues were 1-3 and 300 ppm, respectively. Thus, the dissolved conditions and concentrations of those practical metallic materials in vivo were successfully confirmed.
• Preparation and characteristics of a binderless carbon nanotube monolith and its biocompatibility

  Wei Wang, Atsuro Yokoyama, Susan Liao, Mamoru Omori, Yuhe Zhu, Motohiro Uo, Tsukasa Akasaka, Fumio Watari

  MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS 28 (7) 1082 - 1086 0928-4931 2008/08 [Refereed][Not invited]
   

  A carbon nanotube (CNT) monolith without any binders was obtained by spark plasma sintering (SPS) treatment at 1100 degrees C under 40 MPa pressure. Transmission electron microscope results confirmed that this material maintained the nanosized tube microstructure of raw CNT powder after SPS treatment. The density and mechanical properties of this material were similar to cancellous bone. The material was implanted in subcutaneous tissue and femurs of rats and tissue samples were analyzed by histopathology at I and 4 weeks after surgery. Although some foreign body giant cells were seen around the CNTs, no severe inflammatory response such as necrosis was observed, and CNT implants were surrounded by newly formed bone in the femur. The study provides the first in vivo testing evidence that pure bulk carbon nanotubes are not a strongly inflammatory substance and have no toxicity for bone regeneration. Our study is the first successful experiment to consolidate CNTs without binders, and may provide an effective method for CNT monolith synthesis, as well as demonstrating that a binderless carbon nanotube material with a strength matching that of bone could be a candidate bone Substitute material and a bone tissue engineering scaffold material. (c) 2007 Elsevier B.V. All rights reserved.
• Biochemical and Pathological Responses of Cells and Tissue to Micro‐ and Nanoparticles from Titanium and other Materials

  Fumio Watari, Kazuchika Tamura, Atsruro Yokoyama, Kenichiro Shibata, Tsukasa Akasaka, Bunshi Fugetsu, Kiyotaka Asakura, Motohiro Uo, Yasunori Totsuka, Yoshinori Sato, Kazuyuki Tohji

  Biological Aspects and Structure Formation 127 - 144 2008/03 [Refereed][Not invited]
   

  ISBN: 9783527619443
• Determination of administered organic/inorganic particles in mice

  Shigeaki Abe, Chika Koyama, Mitsue Esaki, Ikuhiro Kida, Iosif Rosca, Tsukasa Akasaka, Motohiro Uo, Manabu Morita, Yoshinori Sato, Balachandran Jeyadevan, Yoshinori Kuboki, Kazuyuki Tohji, Fumio Watari

  8th World Biomaterials Congress 2008 1 460  2008
• Carbohydrate coating of carbon nanotubes for biological recognition

  Tsukasa Akasaka, Fumio Watari

  FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES 16 (2) 114 - 125 1536-383X 2008 [Refereed][Not invited]
   

  We have demonstrated that multi-walled carbon nanotubes (MWNTs) coated with a carbohydrate-carrying polymer for use as biological recognition signals can be easily prepared by a non-covalent method via hydrophobic interactions. Fluorescence observation by confocal laser scanning microscopy showed that the carbohydrate-carrying polymers were densely localized around the MWNTs. To evaluate biological recognition affinity, interactions of the MWNTs with lectins were examined by binding tests. The resultant MWNTs were found to acquire a selective binding affinity to the corresponding lectin without a non-specific interaction. On the other hand, bare MWNTs non-specifically interacted with lectins. These results showed that the MWNTs coated with a carbohydrate-carrying polymer have biological recognition signals. Modification of carbon nanotubes with various carbohydrate chains will be a useful protocol for molecular designs of biomaterials, nanoarchitecture and biosensors.
• Behavior of in vitro, in vivo and internal motion of micro/nano particles of titanium, titanium oxides and others

  Fumio Watari, Shigeaki Abe, Chika Koyama, Atsuro Yokoyama, Tukasa Akasaka, Motohiro Uo, Makoto Matsuoka, Yasunori Totsuka, Mitsue Esaki, Manabu Morita, Tetsu Yonezawa

  JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 116 (1349) 1 - 5 1882-0743 2008/01 [Refereed][Not invited]
   

  To clarify the effect of micro/nanosizing of materials onto biological organism, the particle size dependence of reaction of cells and tissue as investigated by both biochemical cell functional test and animal implantation test. Especially for nanoparticles the behavior of invasion and internal diffusion inside body was visualized using an XSAM (X-ray Scanning Analytical Microscope). The increase of specific surface area is usually counted as nanosizing effect which causes the enhancement of chemical reactivity and therefore toxicity of materials such as carcinogenicity found in 500 nm Ni particles for the long term implantation in the soft tissue of rat. Even biocompatible materials such as Ti and TiO2 shows stimulus with the decrease of particle size. They cause phagocytosis to cells and inflammation to tissue when the size of particles is below 3 mu m. For the size below 50 nm, they may invade into the internal body through the respiratory or digestive system and diffuse inside body. After compulsory exposure test of 30 nm TiO2 particles through the respiratory system, the Ti mapping by XSAM showed the internal diffusion inside the whole body. Nanoparticles injected from caudal vein diffused with time course to lung, liver and spleen. The uptake of 30 nm TiO2 particles through the digestive system and diffusion into these organs was also confirmed. These phenomena observed in biocompatible or bioinert materials are the nonspecific, physical particle and shape effects which occur independent of materials. Nanoparticles might be the objects whose existence has not been assumed by the living body defense system.
• The degradation of the three layered nano-carbonated hydroxyapatite/collagen/PLGA composite membrane in vitro

  Susan Liao, Furnio Watari, Yuhe Zhu, Motohiro Uo, Tsukasa Akasaka, Wei Wang, Guofu Xu, Fuzhai Cui

  DENTAL MATERIALS 23 (9) 1120 - 1128 0109-5641 2007/09 [Refereed][Not invited]
   

  Objective. The purpose of this paper was to investigate the in vitro biodegradation of a guided tissue regeneration composite membrane, nano-carbonated hydroxyapatite/collagen/ poly(lactic - co- glycolic acid) (nCHAC/PLGA). Especially for periodontal therapy, the functional graded material (FGM) nCHAC/PLGA membrane was prepared that consisted of three layers with 8 wt% nCHAC + PLGA/4 wt% nCHAC + PLGA/PLGA, where one face of the membrane is porous, thereby allowing cell growth thereon and the opposite face of the membrane smooth, thereby inhibiting cell adhesion. Methods. For evaluation, in vitro degradation specimens of nCHAC/PLGA were immersed into artificial saliva solution at 37 degrees C for 1, 2, 4, 8 and 12 weeks to detect the weight loss over the period, and set pure PLGA membrane as control to compare the degraded behaviors. pH value and calcium concentration of the residual solution were measured, and morphology change was investigated by scanning electron microscopy (SEM). Results. During the experimental period in vitro, the whole shape of the membrane could be kept for 4 weeks, after that it became powder at between 8 and 12 weeks. The results demonstrated that weight loss increased continuously with a reduction in mass of 23.1% after 4 weeks and 88% after 12 week for the nCHAC/PLGA three FGM layers composite membrane. The calcium concentration in the residual solution showed a significant increase after 4 weeks, which referred to the nano-carbonated hydroxyapatite degradation. Moreover, the pH value in the solution of the nCHAC/PLGA membrane was a little higher than that of the pure PLGA membrane, which demonstrated the possible neutralization effect from nCHAC composite for the acid outcome of PLGA in the solution. The pore structure of 8 wt% nCHAC + PLGA was enlarged on the porous surface, while the nonporous surface of pure PLGA also showed a small porous structure after increased time. Significance. Degradation of the composite membrane is appropriate for practical periodontal repair. Moreover, the new mineral formation on the surface of the composite membrane referred to the possible positive effect in vivo for new bone tissue regeneration. (C) 2006 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
• Carbon nanotubes as scaffolds for cell culture and effect on cellular functions

  Naofumi Aoki, Tsukasa Akasaka, Fumio Watari, Atsuro Yokoyama

  DENTAL MATERIALS JOURNAL 26 (2) 178 - 185 0287-4547 2007/03 [Refereed][Not invited]
   

  To investigate the dependence of blocompatibility of carbon materials on crystal structure with the aim of developing biomedical applications, single-(SW) and multi-walled (MW) carbon nanotubes (CNTs) were employed as scaffolds for cell culture and compared with graphite (GP). SaOS2 cells were used to investigate the properties and response of osteoblast-like cells. Polycarbonate membranes (PC) coated with CNTs by vacuum filtration formed a meshwork nanostructure. Cells grown on CNTs greatly extended in all directions. In terms of cell proliferation, alkaline phosphatase (ALP) activity, and protein adsorption on the substrates, CNTs showed better results than PC and GP. SW showed the best cell proliferation and total ALP. These favorable results might be attributed to the structure of CNTs and the affinity of CNTs toward proteins, thereby suggesting that CNTs could be potential scaffold materials for cell culture.
• X-ray absorption fine structure (XAFS) analysis of titanium-implanted soft tissue

  Motohiro Uo, Kiyotaka Asakura, Atsuro Yokoyama, Makoto Ishikawa, Kazuchika Tamura, Yasunori Totsuka, Tsukasa Akasaka, Fumio Watari

  DENTAL MATERIALS JOURNAL 26 (2) 268 - 273 0287-4547 2007/03 [Refereed][Not invited]
   

  Tissues contacting Ti dental implants were subjected to X-ray absorption fine structure (XAFS) analysis to examine the chemical state of Ti transferred from the placed implant into the surrounding tissue. Nine tissues that contacted pure Ti cover screws for several months were excised in a second surgery whereby healing abutments were set. Six tissues that surrounded implants retrieved due to their failure were also excised. Ti distributions in the excised specimens were confirmed by X-ray scanning analytical microscopy (XSAM), and the specimens were subjected to fluorescence XAFS analysis to determine the chemical states of the low concentrations of Ti in the tissues surrounding Ti dental implants. Ti mostly existed in the metallic state and was considered to be debris derived from the abrasion of implant pieces during implant surgery. Oxidized forms of Ti, such as anatase and rutile, were also detected in a few specimens-and existed in either a pure state or mixed state with metallic Ti. It was concluded that the existence of Ti in the tissue did not cause implant failure. Moreover, the usefulness of XAFS for analysis of the chemical states of rarely contained elements in biological tissue was demonstrated.
• The purity and thermal stability in air of metal-encapsulating carbon nanocapsules (MECNCs)

  Motohiro Uo, Hanako Kachi, Tsukasa Akasaka, Fumio Watari, Yoshinori Sato, Kenichi Motomiya, Kazuyuki Tohji

  FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES 15 (4) 303 - 309 1536-383X 2007 [Refereed][Not invited]
   

  Rare earth elements ( Y, La, Ce, Nd, Gd and Dy) encapsulated by carbon nanocapsules ( CNCs) were synthesized and their purity and air oxidation stability were estimated. The purity was estimated as the rare earth carbide content. Gd- and Dy-encapsulating CNCs had higher than 30 wt% and others 15 to 20 wt%. Encapsulated rare earth carbide was oxidized by heating in air at 400 degrees C or higher. This suggested oxidation damage to the graphene capsules of CNCs.
• Inhibition of growth of Streptococcus mutans with artificial glyco-polymer

  赤坂司

  DE (一社)日本歯科理工学会 161 (161) 35 - 36 0385-0129 2007 [Not refereed][Not invited]
  
• Carbon nanotubes deposited on titanium implant for osteoblast attachment

  Naofumi Aoki, Atsuro Yokoyama, Yoshinobu Nodasaka, Tsukasa Akasaka, Motohiro Uo, Yoshinori Sato, Kazuyuki Tohji, Fumio Watari

  Journal of Bionanoscience 1 (1) 14 - 16 2007 [Refereed][Not invited]
  
• Strikingly extended morphology of cells grown on carbon nanotubes

  Naofumi Aoki, Atsuro Yokoyama, Yoshinobu Nodasaka, Tsukasa Akasaka, Motohiro Uo, Yoshinori Sato, Kazuyuki Tohji, Fumio Watari

  CHEMISTRY LETTERS 35 (5) 508 - 509 0366-7022 2006/05 [Not refereed][Not invited]
   

  The morphology of cells cultured on carbon nanotube (CNTs) scaffolds was investigated using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM) and it was shown that the cells extended strikingly in all directions and numerous filopodia extended far from the cells.
• Apatite formation on carbon nanotubes

  T Akasaka, F Watari, Y Sato, K Tohji

  MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS 26 (4) 675 - 678 0928-4931 2006/05 [Refereed][Not invited]
   

  Apatite coating on carbon-nanotubes (CNTs) was done with a biomimetic coating method. The multi-walled CNTs (MWNTs) of curled shape with about 30 nm in diameter were immersed for 2 weeks in the simulated body fluid. Observation by scanning electron microscopy (SEM) showed the formation of apatite on the MWNTs surface. The clusters of spherules consisting of needle-shaped apatite crystallites were massively grown on the aggregated MWNTs. The crystallites of 100 nm in width and 200-500 nm in length were grown perpendicularly to the longitudinal direction and radially originating from a common center of a single MWNT. Thus, the architecture of crystalline apatite at nano-scale levels could be produced by simple method and the MWNT may be acting as core for initial crystallization of apatite. (c) 2005 Elsevier B.V. All rights reserved.
• X-ray absorption fine structure (XAFS) analyses of Ni species trapped in graphene sheet of carbon nanofibers

  Y. Sato, M. Ohtsubo, B. Jeyadevan, K. Tohji, K. Motomiya, R. Hatakeyama, G. Yamamoto, M. Omori, T. Hashida, K. Tamura, T. Akasaka, M. Uo, A. Yokoyama, F. Watari

  Physical Review B (73) 144103-1 - 144103-11 2006/04 [Refereed][Not invited]
  
• Human neutrophils reaction to the biodegraded nano-hydroxyapatite/collagen and nano-hydroxyapatite/collagen/poly(L-lactic acid) composites

  S Liao, K Tamura, YH Zhu, W Wang, M Uo, T Akasaka, FZ Cui, F Watari

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A 76A (4) 820 - 825 1549-3296 2006/03 [Not refereed][Not invited]
   

  The impact of biodegraded nano-hydroxyapatite/collagen (nHAC) composite and nano-hydroxyapatite/ collagen/poly(L-lactic acid) (nHAC/PLA) scaffold composite on neutrophils reaction was evaluated in vitro. Neutrophils were separated from human peripheral blood of healthy subjects. The nHAC and nHAC/PLA materials were immersed in the D-Hanks' Balanced Salt Solution (DHBSS) for I day, 7 days and 2, 4, 8 weeks (37 degrees C) as testing solution, which mixed with the neutrophils for 1 h. Both of the nHAC and nHAC/PLA materials were shown the same cell Survival rate as blank control, but the lactate dehydrogenase (LDH) and tumor necrosis factor alpha (TNF-alpha) released from the neutrophils were increased significantly after the 2 weeks in nHAC sample. The possible reason relied on the high concentration of calcium due to the quick biodegradation of the nHAC material. Before 2 weeks, the LDH value of nHAC/PLA is higher than that of nHAC sample that corresponded to the initial PLA degradation in vitro. This study provided the biocompatibility test of neutrophils other than common methods, such as osteoblastic cells for biomimetic materials. Moreover, it demonstrated the calcium concentration stimulating effect for cytokine release from neutrophils. (c) 2005 Wiley Periodicals, Inc.
• Functions of Sugar chains in oral cavity

  Tsukasa Akasaka, Fumio Watari

  The journal of dental engineering 159 26 - 28 2006 [Not refereed][Not invited]
  
• Glyco-technology and Dentistry

  Tsukasa Akasaka, Motohiro Uo, Fumio Watari

  Hokkaido Journal of Dental Science 27 (1) 41 - 44 2006 [Not refereed][Not invited]
  
• Cell Culture on a Carbon Nanotube Scaffold

  Naofurni Aoki, Atsuro Yokoyama, Yoshinobu Nodasaka, Tsukasa Akasaka, Motohiro Uo, Yoshinori Sato, Kazuyuki Tohji, Furnio Watari

  JOURNAL OF BIOMEDICAL NANOTECHNOLOGY 1 (4) 402 - 405 1550-7033 2005/12 [Refereed][Not invited]
   

  The developments of nanoscale substance such as carbon nanotubes (CNTs) for medical applications have attracted a great deal of attention. In the present study, an attempt was made to development of CNTs as scaffolds for cell culture. CNT scaffolds were formed on polycarbonate membranes by vacuum filtration and cell proliferation and morphology were investigated using a scanning electron microscopy. Osteoblast cells (bone-forming cell) on CNTs showed excellent proliferation with extension of cell morphology in all directions. Numerous filopodia were extended from cells toward the inside of fibrous aggregates of CNTs and tightly bound to scaffolds. These results suggest that CNTs can be used as scaffolds with excellent affinity for cell adhesion.
• A three-layered nano-carbonated hydroxyapatite/collagen/PLGA composite membrane for guided tissue regeneration

  S Liao, W Wang, M Uo, S Ohkawa, T Akasaka, K Tamura, FZ Cui, F Watari

  BIOMATERIALS 26 (36) 7564 - 7571 0142-9612 2005/12 [Refereed][Not invited]
   

  Functional graded materials (FGM) provided us one new concept for guided tissue regeneration (GTR) membrane design with graded component and graded structure where one face of the membrane is porous thereby allowing cell growth thereon and the opposite face of the membrane is smooth, thereby inhibiting cell adhesion in periodontal therapy. The goal of the present study was to develop a three-layered graded membrane, with one face of 8% nano-carbonated hydroxyapatite/collagen/poly(lactic-co-glycolic acid) (nCHAC/PLGA) porous membrane, the opposite face of pure PLGA non-porous membrane, the middle layer of 4% nCHAC/ PLGA as the transition through layer-by-layer casting method. Then the three layers were combined well with each other with flexibility and enough high mechanical strength as membrane because the three layers all contained PLGA polymer that can be easily used for practical medical application. This high biocompatibility and osteoconductivity of this biodegraded composite membrane was enhanced by the nCHAC addition, for the same component and nano-level crystal size with natural bone tissue. The osteoblastic MC3T3-E1 cells were cultured on the three-layered composite membrane, the primary result shows the positive response compared with pure PLGA membrane. (c) 2005 Elsevier Ltd. All rights reserved.
• Oxidation of multiwalled carbon nanotubes by nitric acid

  ID Rosca, F Watari, M Uo, T Akaska

  CARBON 43 (15) 3124 - 3131 0008-6223 2005/12 [Not refereed][Not invited]
   

  The oxidation of MWCNTs in nitric acid was monitored using sample weight, Raman spectrum. solubility. morphology and alignment. The influence of the acid concentration, temperature and oxidation duration on the monitored parameters was assessed. A new method, based on optical microscopy is proposed for the determination of MWCNT solubility in concentrated aqueous-suspensions. The investigations revealed that the Solubility is determined not only by the functional groups on the MWCNT, but also by the functionalized amorphous carbon generated during the digestion of the nanotubes, High solubility (20-40 mg/ml) is obtained only after prolonged exposure (24-48 h) in concentrated acid (>= 60%). But in these conditions 60-90% of the MWCNTs are lost. Furthermore the MWCNTs are strongly fragmented and covered by amorphous carbon after 48 h of oxidation. It was found that the solubility correlates well with the area ratio of the G and D bands from tile Raman spectrum, SEM examination of the MWCNT films showed extended alignment after 24 h of oxidation. (C) 2005 Elsevier Ltd. All rights reserved.
• Size separation of carbon nanotubes for biomedical application

  Kazuyuki Tohji, Yoshinori Sato, Atsuro Yokoyama, Ken-ichiro Shibata, Shin-ichi Ogino, Kazuchika Tamura, Tsukasa Akasaka, Motohiro Uo, Kenichi Motomiya, Balachandran Jeyadevan, Rikizo. Hatakeyama, Fumio Watari

  Proceedings of International Symposium on EcoTopia Science 2005 1 273 - 276 2005/08/08 [Refereed][Not invited]
  
• Water-soluble hat-stacked carbon nanofibers for biomedical applications

  Yoshinori Sato, Ken-ichiro Shibata, Fugetsu Bunshi, Atsuro Yokoyama, Shin-ichi Ogino, Kazuchika Tamura, Tsukasa Akasaka, Motohiro Uo, Kenichi Motomiya, Balachandran Jeyadevan, Rikizo. Hatakeyama, Fumio Watari, Kazuyuki Tohji

  Proceedings of International Symposium on EcoTopia Science 2005 1 277 - 280 2005/08/08 [Refereed][Not invited]
  
• Strict preparation and evaluation of water-soluble hatstacked carbon nanofibers for biomedical application and their high biocompatibility: influence of nanofiber-surface functional groups on cytotoxicity

  Y Sato, K Shibata, H Kataoka, S Ogino, F Bunshi, A Yokoyama, K Tamura, T Akasaka, M Uo, K Motomiya, B Jeyadevan, R Hatakeyama, F Watari, K Tohji

  MOLECULAR BIOSYSTEMS 1 (2) 142 - 145 1742-206X 2005/07 [Refereed][Not invited]
   

  Water-soluble H-CNFs modified with a carboxyl group possessed the ability to induce TNF-alpha, whereas CHAPS-treated H-CNFs possessed significantly greater activity and were also found to activate NF-kappa B reporter activity, to a significantly greater level than H-CNFs; furthermore the functional group modified or coated on the surface of H-CNFs was a significant cytotoxic factor that affected cell activation.
• Influence of length on cytotoxicity of multi-walled carbon nanotubes against human acute monocytic leukemia cell line THP-I in vitro and subcutaneous tissue of rats in vivo

  Y Sato, A Yokoyama, K Shibata, Y Akimoto, S Ogino, Y Nodasaka, T Kohgo, K Tamura, T Akasaka, M Uo, K Motomiya, B Jeyadevan, M Ishiguro, R Hatakeyama, F Watari, K Tohji

  MOLECULAR BIOSYSTEMS 1 (2) 176 - 182 1742-206X 2005/07 [Refereed][Not invited]
   

  Carbon nanotubes (CNTs) are single- or multi-cylindrical graphene structures that possess diameters of a few nanometers, while the length can be up to a few micrometers. These could have unusual toxicological properties, in that they share intermediate morphological characteristics of both fibers and nanoparticles. To date, no detailed study has been carried out to determine the effect of length on CNT cytotoxicity. In this paper, we investigated the activation of the human acute monocytic leukemia cell line THP-1 in vitro and the response in subcutaneous tissue in vivo to CNTs of different lengths. We used 220 nm and 825 nm-long CNT samples for testing, referred to as "220-CNTs" and "825-CNTs", respectively. 220-CNTs and 825-CNTs induced human monocytes in vitro, although the activity was significantly lower than that of microbial lipopeptide and lipopolysaccharide, and no activity appeared following variation in the length of CNTs. On the other hand, the degree of inflammatory response in subcutaneous tissue in rats around the 220-CNTs was slight in comparison with that around the 825-CNTs. These results indicated that the degree of inflammation around 825-CNTs was stronger than that around 220-CNTs since macrophages could envelop 220-CNTs more readily than 825-CNTs. However, no severe inflammatory response such as necrosis, degeneration or neutrophil infiltration in vivo was observed around both CNTs examined throughout the experimental period.
• Analysis of titanium dental implants surrounding soft tissue using X-ray absorption fine structure (XAFS) analysis

  M Uo, K Asakura, A Yokoyama, K Tamura, Y Totsuka, T Akasaka, F Watari

  CHEMISTRY LETTERS 34 (6) 776 - 777 0366-7022 2005/06 [Refereed][Not invited]
   

  X-ray absorption fine structure (XAFS) analysis was applied for the analysis of titanium (Ti) in the human oral mucosa in contact with Ti dental implants from two different patients. Metallic Ti and an oxide (anatase) were detected. The metallic Ti was distributed in particulate form, which would be debris formed by the abrasion during the operation of implantation. The possibility of using XAFS for the analysis of the chemical state of rarely contained elements in biological tissue was suggested.
• Nano-architecture on carbon nanotube surface by biomimetic coating

  T Akasaka, F Watari

  CHEMISTRY LETTERS 34 (6) 826 - 827 0366-7022 2005/06 [Refereed][Not invited]
   

  Calcium phosphate (Ca-P) coating on carbon nanotubes (CNTs) was done with a biomimetic coating method. The multi-walled CNTs (MWNTs) were immersed for 2 weeks in the simulated body fluid. Observation by scanning electron microscopy showed that needle shape of Ca-P crystallites at nano-scale levels were massively grown on MWNTs. Thus the nano-architecture of crystalline Ca-P on MWNT surface could be produced by simple method and the MWNT may be acting as core for initial crystallization.
• Preparation and Biocompatibility of Sintered Carbon Nanotube Disk

  M. Ohtsubo, Y. Sato, B. Jeyadevan, K. Tohji, R. Hatakeyama, G. Yamamoto, M. Ohmori, T. Hashida, K. Tamura, T. Akasaka, M. Uo, A. Yokoyama, F. Watari

  Fullerenes and Nanotubes –Materials for the New Chemical Frontier-Fullerenes (The Electrochemical Society, Inc.) PV2004-12 243 - 248 2005/03/01 [Not refereed][Invited]
  
• Biological behavior of hat-stacked carbon nanofibers in the subcutaneous tissue in rats

  A Yokoyama, Y Sato, Y Nodasaka, S Yamamoto, T Kawasaki, M Shindoh, T Kohgo, T Akasaka, M Uo, F Watari, K Tohji

  NANO LETTERS 5 (1) 157 - 161 1530-6984 2005/01 [Refereed][Not invited]
   

  The tissue response to hat-stacked carbon nanofibers (H-CNFs) was evaluated. H-CNFs were implanted in the subcutaneous tissue of rats. Histological and ultrastructural investigations were carried out by transmission electron microscopy. Although many macrophages and foreign body giant cells were seen around H-CNFs, no severe inflammatory response such as necrosis was observed. Some H-CNFs were observed in lysosomal vacuoles of phagocytes. These results showed that H-CNFs were not strong prophlogistic substances and were englobed in vivo.
• A novel sintered multi-walled carbon nanotubes bone material by spark plasma sintering method

  W. Wang, A. Yokoyama, M. Omori, S. Liao, Y. Zhu, T. Akasaka, M. Uo, F. Watari

  International Journal of Oral and Maxillofacial Surgery 34 (1) 83  2005 [Refereed][Not invited]
  
• Caged multiwalled carbon nanotubes as the adsorbents for affinity-based elimination of ionic dyes

  B Fugetsu, S Satoh, T Shiba, T Mizutani, YB Lin, N Terui, Y Nodasaka, K Sasa, K Shimizu, R Akasaka, M Shindoh, KI Shibata, A Yokoyama, M Mori, K Tanaka, Y Sato, K Tohji, S Tanaka, N Nishi, F Watari

  ENVIRONMENTAL SCIENCE & TECHNOLOGY 38 (24) 6890 - 6896 0013-936X 2004/12 [Refereed][Not invited]
   

  Multiwalled carbon nanotubes (MWCNTs) were used as the active elements for the first time for affinity-based elimination of ionic dyes. MWCNTs were encapsulated in cross-linked alginate (ALG) microvesicles using Ba2+ as the bridging ion. The Ba2+-alginate matrix constitutes a cage which holds the physically trapped MWCNTs. The cage carries negative charges on its surface. The cage restricts the access of anions of large molecular weight, such as humic acids, because of electrostatic repulsion. The cage also restricts the access of colloids of large size, because of size exclusion. Ionic dyes partition into the cage and then are captured by MWCNTs probably on the basis of van der Waals interactions occurring between the hexagonally arrayed carbon atoms in the graphite sheet of MWCNTs and the aromatic backbones of the dyes. As a result of these interactions the target species, namely, the ionic dyes, are eliminated efficiently by the MWCNTs of Ba2+-ALG/MWCNT composite adsorbents. The adsorptive capacities for elimination of acridine orange, ethidium bromide, eosin bluish, and orange G (the model species used for this study) were found as high as 0.44, 0.43, 0.33, and 0.31 mumol, respectively, for 1.0 mg of the caged MWCNTs. Adsorptive experiments with carbon nanofibers and activated carbons as the adsorbents were also performed. The MWCNT-based adsorbents provided the best capability for the affinity-based elimination of these targeted species. Biocompatibility experiments performed in vitro and in vivo provided promising results, suggesting potential applications of the caged MWCNTs in in situ environmental remediation.
• Distortion of laser welded titanium plates

  K Iwasaki, S Ohkawa, JD Rosca, M Uo, T Akasaka, F Watari

  DENTAL MATERIALS JOURNAL 23 (4) 593 - 599 0287-4547 2004/12 [Refereed][Not invited]
   

  The distortion of laser welded titanium plates was assessed for different operating conditions of the laser welding device, and with different welding parameters (in terms of weld point and prewelding). In this study, Nd : YAG laser welding device was used to join the titanium plates. The results showed that distortion increased stepwise after each welding point along the welding zone (one-side welding), but decreased consecutively as the welding proceeded on the second side of the weld (two-side welding). In the case of one-side welding, the dependence of distortion on current and spot diameter presented maxima - due to changes in the welding pool characteristics. For two-side weld the same parameters exercised little influence on its distortion recovery, due to the effect of solidified weld pools from the first side. Current and spot diameter determined the weld pool, which in turn regulated distortion based on shrinkage. Four-point prewelding significantly decreased the final distortion for both one- and two-side welds. Alternating two-side welding of prewelded assembly showed lower distortion than a classic two-side weld.
• Three-dimensional topographic scanning electron microscope and Raman spectroscopic analyses of the irradiation effect on teeth by Nd : YAG, Er : YAG, and CO2 lasers

  MK Yamada, M Uo, S Ohkawa, T Akasaka, F Watari

  JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS 71B (1) 7 - 15 0021-9304 2004/10 [Refereed][Not invited]
   

  A three-dimensional analyzer installed in a scanning electron microscope was used to evaluate the morphology and surface roughness using noncontact profilometry. Observations were carried out on the enamel and dentin surface irradiated by three different lasers: Nd:YAG (wavelength 1.06 mum), Er:YAG (2.94 mum), and CO2 (10.6 mum). Spectroscopic analysis was done by Raman spectroscopy for nonirradiated and laser-irradiated surfaces. The lasers were applied perpendicularly to vertically sectioned and polished human extracted caries-free molars. The tooth was sectioned at each cavity for cross-section analysis after laser irradiation. Irradiation by Nd:YAG and CO2 lasers of the enamel surface showed an opaque white color, different from dentin where the surface turned black. The Er:YAG laser induced no changes in color of the dentin. Numerous cracks associated with thermal stress were observed in the CO2 laser-irradiated dentin. Noncontact surface profile analysis of Er:YAG laser-irradiated enamel and dentin showed the deepest cavities, and direct cross-sectional observations of them showed similar cavity outlines. The CO2 laser-irradiated dentin had the least surface roughness. Raman spectroscopic analysis showed that fluorescence from the laser-irradiated tooth was generally greater than from nonirradiated teeth. Bands in dentin attributed to organic collagen matrix were lost after Nd:YAG and CO2 laser irradiation, and a broad peak due to amorphous carbon appeared. The Er:YAG laser-irradiated dentin showed no sign of a carbon band and had more suitable results for dental ablation. Noncontact surface profile analysis was effective to evaluate the structural change in the tooth in the microarea of study after laser irradiation. (C) 2004 Wiley Periodicals, Inc.
• Laser welding of titanium and dental precious alloys

  K Iwasaki, S Ohkawa, M Uo, T Akasaka, F Watari

  MATERIALS TRANSACTIONS 45 (4) 1140 - 1146 1345-9678 2004/04 [Not refereed][Not invited]
   

  The performance of laser welding of Ti and two dental precious alloys (Ag-Pd-Au, Au-Pt-Ag) was investigated by mechanical testing and microscopic observation, using butt joint as design. The laser irradiation was done using a commercial Nd:YAG dental laser-welding device in a single pulse mode with output currents 150, 200, 250, 300 A, spot diameters 0.6, 0.9, 1.2 mm, and pulse duration 10 ms. The average welding fracture strength of the dissimilar metals were 108.9 and 137.2 MPa for Ti and Ag-Pd-Au alloy, and Au-Pt-Ag alloy, respectively. The average welding fracture strength of the same metals were 594.9. 648.8 and 312.9 MPa for Ti, Ag-Pd-Au alloy and Au-Pt-Ag alloy. The hardness increased in weld zone, compared with the base metals. Penetration depths were affected by the welding conditions such as the output currents and spot diameters. The welding cracks and porosity were observed in microstructures of the welds. Mapping by EPMA showed the remarkable heterogeneity of the component metals concerned. The welding cracks, porosities and granular precipitates similar to metallic compounds in the weld zones were suggested as the cause for lower welding fracture strength in the dissimilar welds, compared with the similar metals.
• Non-contact surface morphology analysis of CO2 laser-irradiated teeth by scanning electron microscope and confocal laser scanning, microscope

  MK Yamada, M Uo, S Ohkawa, T Akasaka, A Watari

  MATERIALS TRANSACTIONS 45 (4) 1033 - 1040 1345-9678 2004/04 [Not refereed][Not invited]
   

  A newly developed scanning electron microscope (SEM) installed with a 3D analyzer and a confocal laser scanning microscope (CLSM) were used to evaluate the images and surface profiles of enamel and dentin after CO2 laser irradiation. The surface roughness (Ra) was measured and the results were correlated with a stylus profilometer. Raman analysis was done and the laser irradiation effect after acid etching was also examined. Human intact extracted teeth were vertically sectioned. The laser was applied perpendicularly to non-etched and 35% phosphoric acid-etched teeth. The enamel resulted in a crater-like surface. The material was removed in the places where hydroxyapatite crystallites ran parallel to the irradiated surface. Non-etched dentin showed little change after irradiation, with some cracks mostly in the peritubular dentin; whereas in acid-etched dentin there was evaporation of collagen and melting of hydroxyapatite. The SEM and CLSM showed similar profiles and different image contrast. Ra levels obtained by the SEM and CLSM were similar to that obtained with the stylus profilometer. Raman analysis showed that hands of organic collagen matrix on dentin were lost and broad peaks due to carbon were observed. Both the SEM and CLSM provided non-contact evaluation of structural changes of teeth by laser irradiation through surface analysis in selected microareas, which was not possible using the stylus profilometer. Dentin showed more structural changes on the acid-etched surface by irradiation than on the nonetched one.
• Effects of micro/nano particle size on cell function and morphology

  K Tamura, N Takashi, T Akasaka, ID Roska, M Uo, Y Totsuka, F Watari

  BIOCERAMICS, VOL 16 254-2 919 - 922 1013-9826 2004 [Refereed][Not invited]
   

  The cytotoxicity of micro/nano particles in Ti, TiO and carbon nanotube was investigated by in vitro biochemical analyses using human neutrophils. The particles smaller and larger than the neutrophils were used to determine the relationship between cell and particle size with respect to cytotoxicity. As the particle size decreased, the cell survival rate was decreased and, with the good corresponding relation to this, the value of lactate dehydrogenase (LDH), which is the indication of cell disruption, was increased. The release of superoxide anion showed the increasing tendency. Proinflammatory cytokines were detected distinctly for 3 mum or smaller particles and very little in more than 10 mum, which is closely related to the phagocytosis by neutrophils. ICP elemental analysis showed that the dissolution from Ti particles was below detection limit. Micro and nano particles stimulated the cell reactions according to the results of the human neutrophil functional tests. As the particle size was smaller, the inflammation was pronounced. The fine particles less than 3 mum caused distinctly the inflammation in the surrounding tissue. All these results indicated that the cytotoxicity was induced due to the physical size effect of particles, which is different from the ionic dissolution effect. The clinical phenomenon confirmed the result obtained in vitro cell tests. The neutrophils stimulated by fine particles may cause the inflammatory cascade and harm the surrounding tissue.
• Preparation of carbon nanotubes for biomedical applications: Size-separation and their biocompatibilities

  K. Tohji, Y. Akimoto, Y. Sato, B. Jeyadevan, K. Tamura, T. Akasaka, M. Uo, A. Yokoyama, K. - I. Shibata, F. Watari

  Proceedings - Electrochemical Society PV 2004-12 178 - 183 2004 [Refereed][Not invited]
  
• Biocompatibility of carbon nanotube disk

  Y. Sato, M. Ohtsubo, B. Jeyadevan, K. Tohji, K. Motomiya, R. Hatakeyama, G. Yamamoto, M. Omori, T. Hashida, K. Tamura, T. Akasaka, M. Uo, A. Yokoyama, F. Watari

  Proc. SPIE 623 - 627 2004/01 [Refereed][Not invited]
  
• Size separation of carbon nanotubes for biomedical applic applications

  Y. Sato, Y. Akimoto, B. Jeyadevan, K. Motomiya, R. Hatakeyama, K. Tamura, T. Akasaka, M. Uo, A. Yokoyama, K. Shibata, F. Watari, K. Tohji

  Proc. SPIE 13 - 17 2004/01 [Refereed][Not invited]
  
• Synthesis of DNA-Carbohydrate Conjugate via Diazocoupling: A New Class of Modified DNA with Enhanced Stability and Lectin-Recognition Ability

  Kazunori Matsuura, Tsukasa Akasaka, Miki Hibino, Kazukiyo Kobayashi

  Chem.Lett 28 (3) 247 - 248 2003/05 [Refereed][Not invited]
  
• Fine Particles and Bioreaction

  亘理文夫, 田村一央, 高師則行, 宇尾基弘, 赤坂 司, 戸塚靖典, 古月文志, 佐藤義倫, 田路和幸

  ナノ学会会報 2 (1) 34 - 37 2003 [Refereed][Not invited]
  
• Structural analysis of arabinogalactan from Japanese larch in Hokkaido and chemicalfunctionalization of arabinogalactans

  T. Akasaka, Y. Maekawa, S. Nisimura

  Cellul Commun 9 (1) 13 - 17 1342-730X 2002/03 [Refereed][Not invited]
  
• Transformation from block-type to graft-type oligonucleotide-glycopolymer conjugates by self-organization with half-sliding complementary oligonucleotides and their lectin recognition

  T Akasaka, K Matsuura, K Kobayashi

  BIOCONJUGATE CHEMISTRY 12 (5) 776 - 785 1043-1802 2001/09 [Refereed][Not invited]
   

  Block-type oligonucleotide-glycopolymer conjugates bearing alpha -mannosides and beta -galactosides were prepared by coupling 5 ' -thiol-modified oligonucleotides with iodoacetamidated glycopolymers that were synthesized by telomerization. The conjugates minimally affected the DNA conformation and melting behavior of the duplex. Their self-organization via hybridization with the half-sliding complementary oligonucleotides produced graft-type conjugates or macromolecular gapped DNA duplexes grafted with glycopolymers at regular intervals, which was confirmed using size exclusion chromatography and electrophoresis. The binding affinity of block-type and self-organized graft-type conjugates to lectins was investigated using fluorometry. The affinity of the graft-type duplex assembly bearing mannosides to Con A was approximately 2 times stronger than that of block-type single-stranded or double-stranded conjugates with full complementary oligonucleotides. The organization strategy of DNA-glycopolymer conjugates might be useful for constructing novel glyco-clusters and also for developing a new methodology for gene therapy.
• Facile synthesis of stable and lectin-recognizable DNA-carbohydrate conjugates via diazo coupling

  K Matsuura, T Akasaka, M Hibino, K Kobayashi

  BIOCONJUGATE CHEMISTRY 11 (2) 202 - 211 1043-1802 2000/03 [Refereed][Not invited]
   

  Stable and lectin-recognizable DNA-carbohydrate conjugates were prepared by diazo coupling of lactose and cellobiose derivatives to fragmented salmon testes DNA. The diazo coupling is suggested to take place selectively to guanine bases since the amount of lactose moiety introduced was directly proportional to the G content of various DNAs with different G contents. According to the CD spectra, the conjugates bearing carbohydrate less than 25% content kept a typical B-type conformation similar to native DNA. The conjugates possessed higher melting temperature and stronger nuclease resistance both to exo- and endonucleases than native DNA. Gel shift assay and fluorescence binding assay showed that the DNA-lactose conjugates were specifically bound to galactose-specific lectin RCA(120) with strong binding affinity (K-a = 10(4)-10(5) M-1) due to glycoside cluster effect. This facile method will be a useful protocol of molecular design for cell-targeted gene therapy.
• Conjugation of plasmid DNAs with lactose via diazocoupling enhances resistance to restriction enzymes and acquires binding affinity to galactose-specific lectin

  T Akasaka, K Matsuura, N Emi, K Kobayashi

  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 260 (2) 323 - 328 0006-291X 1999/07 [Refereed][Not invited]
   

  Oligosaccharide-plasmid DNA conjugates were synthesized simply and effectively via the diazocoupling method. Plasmids (pUC19, pTRI-beta-actin, and pEGFP-C1) were treated with an N-beta-lactoside-substituted diazonium salt to yield diazocoupling products with degree of substitutions of 2.5-3.1 mol% of overall nucleobases. The lactose-pUC19 conjugate was found to resist restriction enzymes more strongly than the nonconjugated plasmid DNA and to acquire a strong binding affinity to galactose-specific lectin RCA(120). The diazocoupling modification of pTRI-beta-actin plasmid DNA little influenced in vitro transcription with T7 RNA polymerase. When lactose-pEGFP-C1 conjugate was transfected to baby hamster kidney (BHK) cells by means of cationic lipids, transduced gene was expressed in BHK cells similarly with the nonconjugated pEGFP-C1. The modification of plasmid DNA with carbohydrate enhanced the resistance to restriction enzymes and developed a strong binding affinity to galactose-specific lectin. (C) 1999 Academic Press.
• Synthesis of polymethacrylate derivatives having sulfated maltoheptaose side chains with anti-HIV activities

  T Yoshida, T Akasaka, Y Choi, K Hattori, B Yu, T Mimura, Y Kaneko, H Nakashima, E Aragaki, M Premanathan, N Yamamoto, T Uryu

  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 37 (6) 789 - 800 0887-624X 1999/03 [Refereed][Not invited]
   

  Anti-HIV (human immunodeficiency virus) active polymethacrylates having pendant sulfated oligosaccharides were synthesized, and the relationship between structures and biological activities of the polymethacrylates was examined. Acetylated 1-O-methacryloyl maltoheptaoside (MA-AcM7) was polymerized with AIBN as an initiator to give polymethacrylates having a pendant acetylated maltoheptaose in every repeating unit, poly(MA-AcM7)s. After hydroxyl groups were recovered by deacetylation, the polymethacrylates having maltoheptaose units, poly(MA-M7)s, were sulfated to give polymethacrylates having sulfated maltoheptaose side-chains, poly(MA-SM7)s, with degrees of sulfation of 1.1 to 2.7 (maximum, 3.0). These polymethacrylates including sulfated oligosaccharides exhibited low anti-HIV activities represented by the 50% protecting concentration (EC50) in the range of 15-62 mu g/mL and low blood anticoagulant activities around 10 unit/mg (standard dextran sulfate, 22.7 unit/mg). The anti-HIV activity increased with increasing degree of sulfation to reach EC50 of 15-16 mu g/mL. In addition, copolymerization of MA-AcM7 with methyl methacrylate (MMA) and subsequent sulfation gave polymethacrylates consisting of various proportions of highly sulfated maltoheptaose and MMA units. It was revealed that the anti-HIV activity increased with decreasing proportion of the sulfated oligosaccharide moiety and that a copolymethacrylate having 22 mol % of sulfated maltoheptaose units (DS = 3.0) had a high anti-HIV activity in the EC50 of 0.3 mu g/mL. The blood anticoagulant activity increased slightly from 9 to 18 unit/mg with decreasing proportion of the sulfated maltoheptaose units. These results suggested that the biological activities were influenced strongly by the spatial distance between sulfated oligosaccharide substituents in the polymethacrylate main chain. Distinction and conformation of the oligosaccharide side chains also played an important role. (C) 1999 John Wiley & Sons, Inc.

MISC

• ヒトI型コラーゲン様リコンビナントペプチド/β-三リン酸カルシウム骨補填材による歯周組織再生効果

  吉野友都, 宮治裕史, 西田絵利香, 金本佑生実, 浜本朝子, 加藤昭人, 菅谷勉, 赤坂司  日本歯周病学会会誌(Web)  65-  2023
• 温度応答性歯科矯正用解体性接着材の開発

  春藤 彩花, 中西 康, 金子 知生, 黒川 考幸, 松本 愛子, 遠藤 諒俊, 赤坂 司, 吉田 靖弘, 佐藤 嘉晃  日本矯正歯科学会大会プログラム・抄録集  81回-  177  -177  2022/10
• 前駆体利用バイオミメティックプロセスによる低結晶性アパタイト成膜足場材 骨・歯周組織形成能の評価

  金本 佑生実, 宮治 裕史, 西田 絵利香, 宮田 さほり, 眞弓 佳代子, 吉野 友都, 加藤 昭人, 菅谷 勉, 赤坂 司, 大矢根 綾子  日本歯周病学会会誌  64-  (秋季特別)  122  -122  2022/08
• Surface pre-reacted glass-ionomer(S-PRG)ナノフィラー分散液を注水に用いた超音波スケーラーによる歯周炎改善効果

  宮治 裕史, 眞弓 佳代子, 金本 佑生実, 岡本 一絵, 浜本 朝子, 加藤 昭人, 菅谷 勉, 赤坂 司, 田中 佐織  日本歯周病学会会誌  64-  (秋季特別)  126  -126  2022/08
• 微細構造が破骨細胞への分化に与える影響

  赤坂 司, 中西 康, 吉田 靖弘  北海道外科雑誌  67-  (1)  95  -95  2022/06
• 微細構造が破骨細胞への分化に与える影響

  赤坂 司, 中西 康, 吉田 靖弘  北海道外科雑誌  67-  (1)  95  -95  2022/06
• パイロジェンフリー・非動物由来生体吸収性材料の開発

  中西 康, 赤坂 司, 吉原 久美子, 中村 真理子, 吉田 靖弘  日本歯科理工学会誌  41-  (Special Issue79)  13  -13  2022/05
• 破骨細胞様細胞への分化へ影響を与えるマイクロ・ナノパターンの探索

  赤坂 司, 横山 敦郎, 中西 康, 吉田 靖弘  日本歯科理工学会誌  41-  (Special Issue79)  31  -31  2022/05
• Dental innovation at Hokkaido University

  吉田靖弘, 吉田靖弘, 中西康, 中西康, 赤坂司, 日下輝雄, 日下輝雄, 日下輝雄, 山本照子, 山本照子, 山本照子  日本歯科医学会連合雑誌  1-  2022
• 前駆体利用バイオミメティックプロセスによる低結晶性アパタイト成膜足場材-骨・歯周組織形成能の評価-

  金本佑生実, 宮治裕史, 西田絵利香, 宮田さほり, 眞弓佳代子, 吉野友都, 加藤昭人, 菅谷勉, 赤坂司, 大矢根綾子  日本歯周病学会会誌(Web)  64-  2022
• 破骨細胞の吸収窩形成へのマイクロ・ナノパターンの影響

  赤坂 司, 中西 康, 吉田 靖弘  日本歯科理工学会誌  40-  (Special Issue77)  31  -31  2021/03
• 北海道・東北地方会5大学の教育への取り組み—Current dental materials education in five dental schools in Hokkaido and Tohoku branch

  遠藤 一彦, 鈴木 治, 石田 喜紀, 高橋 正敏, 澤田 智史, 武本 真治, 赤坂 司, 根聿 尚史  日本歯科理工学会誌 = The journal of the Japanese Society for Dental Materials and Devices / 日本歯科理工学会 編  40-  (1)  85  -94  2021/01
• S-PRGナノフィラーを用いた抗菌性歯面コーティングによる臨床パラメーターの改善-イヌ実験的歯周炎における検討-

  眞弓佳代子, 宮治裕史, 宮田さほり, 西田絵利香, 降旗友和, 金本佑生実, 菅谷勉, 蔀佳奈子, 赤坂司  日本歯周病学会会誌(Web)  63-  2021
• リゾチーム-金ナノクラスター/ローズベンガル複合体の抗菌・抗バイオフィルム光線力学的活性

  岡本一絵, 宮治裕史, 宮田さほり, 菅谷勉, 蔀佳奈子, 赤坂司, 齋田慧, 川崎英也  日本歯周病学会会誌(Web)  63-  2021
• マイクロ・ナノパターンが骨系細胞に与える影響について

  沼本真一郎, 横山敦郎, 赤坂司, 吉田靖弘  北海道外科雑誌  66-  (1)  2021
• 破骨細胞分化誘導へのマイクロ・ナノパターンの影響

  赤坂 司, 玉井 美保, 吉田 靖弘  日本歯科理工学会誌  39-  (Special Issue75)  8  -8  2020/04
• マイクロブラシ状コラーゲンからなる人工歯根膜を持つインプラントの開発

  赤坂 司  医科学応用研究財団研究報告  37-  36  -41  2020/02
• Surface modification of tooth by nanoimprinting and cell response

  赤坂司  砥粒加工学会誌  64-  (12)  2020
• Trial produce of micro/nano-patterns to screening in initial evaluation of cell functions for biomedical applications

  赤坂司, 伊東駿也, 中川勝, 宮内昭浩  生体医歯工学共同研究拠点成果報告会  2019-  2020
• マイクロブラシ状コラーゲンからなる人工歯根膜を持つインプラントの開発

  赤坂司  医科学応用研究財団研究報告(CD-ROM)  37-  2020
• β-TCPナノ粒子配合ヒトI型コラーゲン様リコンビナントペプチド骨補填材による骨形成効果

  降籏 友和, 宮治 裕史, 西田 絵利香, 加藤 昭人, 宮田 さほり, 蔀 佳奈子, 眞弓 佳代子, 金本 佑生実, 菅谷 勉, 赤坂 司  日本歯周病学会会誌  61-  (秋季特別)  126  -126  2019/10  [Not refereed][Not invited]
  
• β-TCPナノ粒子配合ヒトI型コラーゲン様リコンビナントペプチド骨補填材による骨形成効果

  降籏 友和, 宮治 裕史, 西田 絵利香, 加藤 昭人, 宮田 さほり, 蔀 佳奈子, 眞弓 佳代子, 金本 佑生実, 菅谷 勉, 赤坂 司  日本歯周病学会会誌  61-  (秋季特別)  126  -126  2019/10  [Not refereed][Not invited]
  
• β‐TCPナノ粒子配合ヒトI型コラーゲン様リコンビナントペブチド骨補填材による骨形成効果

  降籏友和, 宮治裕史, 西田絵利香, 加藤昭人, 宮田さほり, 蔀佳奈子, 眞弓佳代子, 金本佑生実, 菅谷勉, 赤坂司  日本歯周病学会会誌(Web)  61-  126  2019/10/01  [Not refereed][Not invited]
  
• マイクロ・ナノ構造への血液関連細胞の付着性

  赤坂 司, 玉井 美保, 吉田 靖弘  日本歯科理工学会誌  38-  (Special Issue74)  34  -34  2019/09
• ナノポーラス物質含有による歯科用シーラント材料から薬剤徐放特性の検討

  江良 裕子, 中西 康, 阿部 薫明, 玉井 美保, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  38-  (Special Issue74)  47  -47  2019/09
• Groove/Pillarパターン化チタン表面が細胞接着及び増殖に与える影響

  加我 公行, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  38-  (Special Issue73)  37  -37  2019/04
• カゴ状ナノシリカ粒子を用いた薬剤徐放性歯科材料の開発

  江良 裕子, 阿部 薫明, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  38-  (Special Issue73)  43  -43  2019/04
• マイクロ・ナノ構造が歯周組織関連細胞の挙動にもたらす影響

  高田 亮, 赤坂 司, 山方 秀一, 佐藤 嘉晃, 吉田 靖弘  北海道歯学雑誌  39-  (2)  167  -167  2019/03
• マイクロ・サブミクロパターン構造を付与したCOP film上における細胞挙動

  本間 淳, 赤坂 司, 山方 秀一, 佐藤 嘉晃, 吉田 靖弘  北海道歯学雑誌  39-  (2)  167  -167  2019/03
• マイクロ・ナノパターンに対する血液関連細胞の細胞接着

  赤坂司  砥粒加工学会学術講演会講演論文集(CD-ROM)  2019-  2019
• マイクロ・ナノパターン表面構造における細胞応答

  加我公行, 赤坂司, 吉田靖弘, 横山敦郎  北海道外科雑誌  64-  (1)  2019
• Bone forming ability of human type-I collagen-like recombinant peptide granules and submicron β-TCP

  西田絵利香, 宮治裕史, 降籏友和, 加藤昭人, 宮田さほり, 蔀佳奈子, 眞弓佳代子, 金本佑生実, 菅谷勉, 赤坂司  日本バイオマテリアル学会大会予稿集(Web)  41st-  2019
• ナノβ‐TCP/ヒトI型コラーゲン様リコンビナントペプチド顆粒の骨形成特性評価

  西田絵利香, 宮治裕史, 降籏友和, 宮田さほり, 加藤昭人, 金本佑生実, 菅谷勉, 赤坂司  日本再生医療学会総会(Web)  18th-  ROMBUNNO.P‐02‐099 (WEB ONLY)  2019  [Not refereed][Not invited]
  
• マイクロ・ナノ構造が細胞接着にもたらす影響

  高田 亮, 赤坂 司, 山方 秀一, 佐藤 嘉晃, 飯田 順一郎, 吉田 靖弘  日本矯正歯科学会大会プログラム・抄録集  77回-  256  -256  2018/10
• 多孔質シリカを用いた選択的薬剤徐放を実現する歯科用材料の開発

  江良 裕子, 中西 康, 阿部 薫明, 玉井 美保, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  37-  (Special Issue72)  56  -56  2018/09
• ユウロピウム錯体を用いた矯正歯科用蛍光ボンディング材の試作

  松本 愛子, 山方 秀一, 佐藤 嘉晃, 阿部 薫明, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  37-  (Special Issue72)  107  -107  2018/09
• 歯科材料に混合したナノポーラス物質からの薬剤徐放特性の追跡

  江良 裕子, 中西 康, 阿部 薫明, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  37-  (Special Issue71)  53  -53  2018/03
• キャピラリーフォースによるマイクロピラー自己組織化による培養担体の調製

  赤坂 司, 玉井 美保, 阿部 薫明, 吉田 靖弘  日本歯科理工学会誌  37-  (Special Issue71)  72  -72  2018/03
• 薬剤徐放能を持つ多孔質シリカを用いた歯科用材料の開発

  江良裕子, 坂東洋祐, 中西康, 阿部薫明, 玉井美保, 赤坂司, 飯田順一郎, 吉田靖弘  化学系学協会北海道支部冬季研究発表会(Web)  2018-  2018
• リゾチーム金ナノクラスター/ローズベンガル複合体の創製と光線力学的評価

  岡本一絵, 宮治裕史, 宮田さほり, 蔀佳奈子, 川崎英也, 赤坂司, 菅谷勉  日本バイオマテリアル学会大会予稿集(Web)  39回-  132  -132  2017/11  [Not refereed][Not invited]
  
• ナノポーラス物質を用いたグラスアイオノマーセメントマトリックスからの薬剤モデル物質の徐放挙動

  江良 裕子, 中西 康, 阿部 薫明, 玉井 美保, 赤坂 司, 吉田 靖弘  日本歯科理工学会誌  36-  (5)  356  -356  2017/09
• 硬化可能な歯科材料によるマイクロ・ナノパターニング

  赤坂 司, 加我 公行, 横山 敦郎, 阿部 薫明, 吉田 靖弘  日本歯科理工学会誌  36-  (2)  82  -82  2017/03
• Micro/nano-patterning of gelatin by crosslinking with genipin

  赤坂司, 阿部薫明, 吉田靖弘  日本歯科理工学会誌  36-  (5)  2017
• ゲニピン添加マイクロ・ナノパターン化ゼラチン上での細胞接着

  蒔田玲果, 赤坂司, 宮治裕史, 宮田さほり, 菅谷勉  日本バイオマテリアル学会シンポジウム予稿集  2016-  142  -142  2016/11/21  [Not refereed][Not invited]
  
• 歯表面での3D微細構造構築によるバイオミメティック次世代歯科治療へ向けて

  赤坂司, 加我公行, 宮治裕史, 横山敦郎, 吉田靖弘  日本歯科医学会誌  35-  36  -36  2016/03/31  [Not refereed][Not invited]
  
• Electroconductive treatment for SEM observation of wet-biological samples using room temperature ionic liquids-

  江良裕子, 阿部薫明, 川上隼人, 河合功治, 赤坂司, 吉田靖弘  日本歯科理工学会誌  35-  (2)  135  -135  2016/03/25  [Not refereed][Not invited]
  
• Cell aggregation of periodontal ligament fibroblasts controlled by micro-patterns

  赤坂司, 加我公行, 横山敦郎, 阿部薫明, 吉田靖弘  日本歯科理工学会誌  35-  (2)  134  -134  2016/03/25  [Not refereed][Not invited]
  
• A novel drug controlled release system using phoshorylated polysaccharides

  阿部薫明, 沖原巧, 赤坂司, 吉田靖弘  日本歯科理工学会誌  35-  (2)  128  -128  2016/03/25  [Not refereed][Not invited]
  
• 金クラスターとLED光照射器による光殺菌歯科治療法の開発

  宮田さほり, 宮治裕史, 西田絵利香, 川崎英也, 山本真希, 滝田裕子, 牛島夏未, 岩永俊彦, 赤坂司, 田中佐織, 川浪雅光  日本バイオマテリアル学会大会予稿集  37th-  183  -183  2015/11/09  [Not refereed][Not invited]
  
• マイクロパターンにおける歯根膜線維芽細胞の細胞配向および移動

  赤坂 司, 加我 公行, 横山 敦郎, 阿部 薫明, 吉田 靖弘  日本歯科理工学会誌  34-  (5)  397  -397  2015/09
• Behavior of cell adhesion on micro/nano-patterned materials

  赤坂司, 加我公行, 阿部薫明, 吉田靖弘  日本歯科理工学会誌  34-  (2)  58  -58  2015/03/25  [Not refereed][Not invited]
  
• Biocompatibility and Toxicity of Nanobiomaterials 2014

  Xiaoming Li, Sang Cheon Lee, Shuming Zhang, Tsukasa Akasaka  JOURNAL OF NANOMATERIALS  2015-  2015  [Not refereed][Not invited]
  
• Effects of cell type on cell adhesion of micro/nano-patterned composite resin

  赤坂司, 加我公行, 阿部薫明, 吉田靖弘  日本歯科理工学会誌  33-  (5)  466  -466  2014/09/20  [Not refereed][Not invited]
  
• Development of protein stock solution using ionic liquids: A long-term stability of proteins at room temperature

  阿部薫明, 金子恒太郎, 河合功治, 赤坂司, 吉田靖弘  日本歯科理工学会誌  33-  (5)  446  -446  2014/09/20  [Not refereed][Not invited]
  
• Fabrication of micro/nano-patterned gelatin for cell adhesion studies

  加我公行, 赤坂司, 横山敦郎, 吉田靖弘  日本歯科理工学会誌  33-  (5)  464  -464  2014/09/20  [Not refereed][Not invited]
  
• 【続・バイオマテリアルの境界科学】固体高分子表面の微細構造による細胞応答

  赤坂 司  バイオマテリアル-生体材料-  32-  (3)  163  -173  2014/07  

  バイオ分野で微細構造を持った高分子の作製やその活性評価が盛んに行われている。ランダムな微細構造を固体高分子表面に作製するには、マイクロ・ナノ物質で表面コートする方法が簡便である。また、設計された精密な微細構造を作製するには、ナノインプリントが量産可能であるため利用されている。その際、合成高分子および天然高分子を材料に用いる利点は多い。細胞培養中に微細構造の表面は、特有なタンパク吸着挙動を示し、細胞の形や核の位置、メカニカルストレスなどに影響を及ぼす。その結果、細胞の配列・接着・伸展・増殖・移動・分化などの細胞応答に影響を与える。(著者抄録)
• イオン液体を用いたバイオマテリアルのSEM新規観察法の開発

  兵野 篤, 米澤 徹, 阿部 薫明, 赤坂 司, 亘理 文夫  北海道外科雑誌  59-  (1)  91  -92  2014/06
• マイクロ・ナノパターンを付与したコンポジットレジン上への細胞接着

  今村琢也, 宮治裕史, 赤坂司, 西田絵利香, 長尾敬志, 川浪雅光  日本歯周病学会学術大会プログラムおよび講演抄録集  57th-  (春季特別)  120  -120  2014/04/08  [Not refereed][Not invited]
  
• マイクロ・ナノパターン化コンポジットレジンへの細胞接着

  赤坂 司, 亘理 文夫  日本歯科理工学会誌  33-  (2)  120  -120  2014/03
• セラミックナノ粒子の細胞刺激性の検討

  阿部 薫明, 岩寺 信喜, 半場 悠介, 山方 秀一, 赤坂 司, 八若 保孝, 飯田 順一郎, 亘理 文夫, 古月 文志  日本歯科理工学会誌  33-  (2)  162  -162  2014/03
• Biocompatibility and Toxicity of Nanobiomaterials 2013

  Xiaoming Li, Sang Cheon Lee, Shuming Zhang, Tsukasa Akasaka  JOURNAL OF NANOMATERIALS  2014-  2014  [Not refereed][Not invited]
  
• Polymeric Scaffolds for Tissue Engineering

  Xiaoming Li, Tsukasa Akasaka, Nicholas Dunne  INTERNATIONAL JOURNAL OF POLYMER SCIENCE  2014-  2014  [Not refereed][Not invited]
  
• キトサンを用いたマイクロパターン化フィルムの作製

  西田絵利香, 宮治裕史, 赤坂司, 川浪雅光  日本バイオマテリアル学会大会予稿集  35th-  459  -459  2013/11/25  [Not refereed][Not invited]
  
• ユウロピウム錯体を用いた歯科矯正用ボンディング材への蛍光特性の付与

  半場 悠介, 山方 秀一, 中西 康, 赤坂 司, 飯田 順一郎, 亘理 文夫  日本矯正歯科学会大会プログラム・抄録集  72回-  215  -215  2013/10
• マイクロ・ナノパターン化したアパタイト担体への細胞接着

  赤坂 司, 亘理 文夫  日本歯科理工学会誌  32-  (5)  344  -344  2013/09
• 歯科応用に向けたポリ乳酸/層状ケイ酸塩ナノコンポジットの試作

  中西 康, 山方 秀一, 半場 悠介, 赤坂 司, 亘理 文夫, 飯田 順一郎  日本歯科理工学会誌  32-  (5)  372  -372  2013/09
• 骨芽細胞へと曝露したマイクロ/ナノマテリアルの生体刺激性の検討

  阿部 薫明, 岩寺 信喜, 半場 悠介, 山方 秀一, 赤坂 司, 八若 保孝, 飯田 順一郎, 亘理 文夫  日本歯科理工学会誌  32-  (5)  373  -373  2013/09
• ヒト上皮3次元培養組織モデルを用いた生体材料‐軟組織間の封鎖性評価

  古橋一憲, 北川善政, 赤坂司, 亘理文夫, 青沼仁志  北海道外科雑誌  58-  (1)  87  -88  2013/06/20  [Not refereed][Not invited]
  
• ナノ微粒子に対する細胞応答 タイムラプス法による動的挙動連続観察

  岩寺 信喜, 伊藤 佐智子, 八若 保孝, 赤坂 司, 亘理 文夫  北海道外科雑誌  58-  (1)  89  -89  2013/06
• 歯科矯正用ボンディング材の視認性向上に向けた試み

  半場 悠介, 山方 秀一, 赤坂 司, 宇尾 基弘, 飯田 順一郎, 亘理 文夫  日本歯科理工学会誌  32-  (2)  111  -111  2013/03
• 最新の歯学 マイクロ・ナノパターン化バイオマテリアルの歯科領域での応用

  赤坂 司, 亘理 文夫  北海道歯学雑誌  33-  (2)  189  -191  2013/03  [Not refereed][Not invited]
  
• Preparation of patterned biomaterials with micro- and nano-topographies

  赤坂司, 阿部薫明, 亘理文夫  日本歯科理工学会誌  32-  (2)  2013
• チタン製の人工骨・人工歯根が骨に結合する生化学的メカニズム

  久保木芳徳, 古沢利武, 佐藤正明, 孫永こん, 鵜沼英郎, 滝田裕子, 藤澤隆一, 阿部薫明, 赤坂司, 亘理文夫, SAMMONS Rachel L.  北海道外科雑誌  58-  (1)  2013
• SEM observation of biological samples using room temperature ionic liquids

  ABE SHIGEAKI, HYONO ATSUSHI, AKASAKA TSUKASA, WATARI FUMIO, YONEZAWA TETSU  日本歯科理工学会誌  31-  (5)  442  -442  2012/09/25  [Not refereed][Not invited]
   

  Ionic liquid is a kind of salt as a liquid even at room temperature. Because of their unique properties such as fluidity, high ionic conductivity and negligible vapor pressure, they have been attention for widely applications even under vacuum conditions. In this study, we investigated the ionic liquid for SEM pretreatment of several biomaterials. With regard to IL coating on the sample surface, we succeeded in high-quality observation of biomaterials. In addition, we also succeeded in applying the IL preparation to SEM-EDS measurement. These results suggested that this simple and rapid conductivity preparation for SEM observation.
• P-9 Evaluation of adhesion between biomaterial and epithelium using human 3D epidermal model

  Furuhashi K, Akasaka T, Kitagawa Y, Watari F  The journal of the Japanese Society for Dental Materials and Devices  31-  (5)  392  -392  2012/09/25  [Not refereed][Not invited]
   

  The development of nanotechnology has created various nano-scaled biomaterials. Micro/nanosizing of biomaterials can enhance function ability compared to macro size materials. In this study, nano-scaled hydroxyapatite (SHAp) composite polymer and 3D epidermal tissue model were used for cell culture experiment to evaluate the closure between biomaterial and epithelial. Using fibroblast and epidermal keratinocyte progenitor cells, cellular adhesiveness was examined. SHAp was observed to adhere to 3D epidermal model through the keratinized layer.
• Anti-bacterial activity of chitosan film with nano-structure

  AKASAKA TSUKASA, ABE SHIGEAKI, WATARI FUMIO  日本歯科理工学会誌  31-  (5)  367  -367  2012/09/25  [Not refereed][Not invited]
  
• 蛍光特性を有する歯科矯正用ボンディング材の特性評価

  半場 悠介, 山方 秀一, 赤坂 司, 宇尾 基弘, 飯田 順一郎, 亘理 文夫  日本歯科理工学会誌  31-  (5)  368  -368  2012/09
• カーボンナノチューブ薄膜上での細胞培養

  赤坂司, 阿部薫明, 亘理文夫, 橋本剛  北海道外科雑誌  57-  (1)  88  -88  2012/06/20  [Not refereed][Not invited]
  
• A-23 Cellular behavior on nano-scaled hydroxyapatite composite materials

  Furuhashi K, Akasaka T, Kitagawa Y, Watari F  The journal of the Japanese Society for Dental Materials and Devices  31-  (2)  136  -136  2012/03/25  [Not refereed][Not invited]
   

  The development of nanotechnology has created various nano-scaled biomaterials. Micro/nanosizing of biomaterials can enhance function ability compared to macro size materials. In this study, nano-scaled hydroxyapatite (SHAp) composite polymer and 3D epidermal tissue model were used for cell culture experiment to evaluate the cellular adhesiveness. Using fibroblast and epidermal keratinocyte progenitor cells examined cellular behavior (mainly cellular adhesiveness). SEM observation showed that more cells were attached and extended larger. Many fines filopodias were developed from the cells. These suggest a strong cell adhesive capacity of SHAp.
• Cell culture with carbon nanotube films and cell manipulation

  AKASAKA TSUKASA, ABE SHIGEAKI, WATARI FUMIO  日本歯科理工学会誌  31-  (2)  91  -91  2012/03/25  [Not refereed][Not invited]
  
• カーボンナノチューブのバイオ応用

  赤坂司  北海道歯学雑誌  32-  (2)  235  -236  2012/03/15  [Not refereed][Not invited]
  
• 歯科矯正用ボンディング材への蛍光性物質の添加効果

  半場 悠介, 山方 秀一, 赤坂 司, 宇尾 基弘, 飯田 順一郎, 亘理 文夫  日本歯科理工学会誌  31-  (2)  85  -85  2012/03
• マイクロ/ナノ粒子曝露下の骨芽細胞様細胞と肝細胞の影響

  岩寺 信喜, 阿部 薫明, 石川 紘佑, 赤坂 司, 宇尾 基弘, 八若 保孝, 亘理 文夫  日本歯科理工学会誌  31-  (2)  97  -97  2012/03
• タンパク質とチタンの反応 インプラント定着の機構解明を目指して

  久保木 芳徳, 古沢 利武, 佐藤 正明, 孫 永こん, 鵜沼 英郎, 滝田 裕子, 藤澤 隆一, 阿部 薫明, 赤坂 司, 亘理 文夫  北海道歯学雑誌  32-  (2)  250  -251  2012/03
• 放電プラズマ焼結した歯科用ジルコニアセラミックスの微細欠陥と寸法精度評価

  宇尾基弘, 亘理文夫, 赤坂司, 阿部薫明, 後藤孝, 木村久道, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2011-  2012
• Interaction between carbon nanotubes and biomolecules: An in vitro and in silico study

  阿部薫明, 小峰梨果, 石川紘佑, 赤坂司, 亘理文夫, 田地川浩人  日本歯科理工学会誌  31-  (2)  2012
• Preference of adsorbed protein on carbon nanotubes

  森川真衣, 久保木芳徳, 赤坂司, 阿部薫明, 亘理文夫  日本歯科理工学会誌  31-  (2)  2012
• Biocompatibility and Toxicity of Nanobiomaterials

  Xiaoming Li, Sang Cheon Lee, Shuming Zhang, Tsukasa Akasaka  JOURNAL OF NANOMATERIALS  2012-  2012  [Not refereed][Not invited]
  
• 多層カーボンナノチューブの骨髄間質細胞への影響

  平田 恵理, 赤坂 司, 滝田 裕子, 宇尾 基弘, 亘理 文夫, 横山 敦郎  日本バイオマテリアル学会大会予稿集  33回-  383  -383  2011/11
• P-46 Development of a novel SEM observation using an ionic liquid

  Abe S, Hyono A, Akasaka T, Watari F, Yonezawa T  The journal of the Japanese Society for Dental Materials and Devices  30-  (5)  349  -349  2011/09/25  [Not refereed][Not invited]
   

  Ionic liquid is a kind of salt as a liquid even at room temperature. Because of their unique properties such as negligible vapor pressure at room temperature and high ionic conductivity, they have been attention for widely applications even under vacuum conditions. In this study, we investigated the ionic liquid for treatment of insulating SEM samples. Ionic liquid was found to put electrical conductivity to the samples similar to a metal or carbon coating.
• ポリ乳酸の分解生成物の解析

  佐々木 朗子, 阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫  日本歯科理工学会誌  30-  (5)  317  -317  2011/09
• マイクロ・ナノ無機粒子の各種細胞への影響

  岩寺 信喜, 阿部 薫明, 石川 紘佑, 赤坂 司, 宇尾 基弘, 八若 保孝, 亘理 文夫  日本歯科理工学会誌  30-  (5)  318  -318  2011/09
• カーボンナノチューブ培養担体への誘電泳動を用いた細胞集積

  松岡真琴, 赤坂司, 橋本剛, 亘理文夫, 戸塚靖則  ナノ学会大会講演予稿集  9th-  297  2011/06/02  [Not refereed][Not invited]
  
• カーボンナノチューブ薄膜上での細胞培養

  赤坂司, 松岡真琴, 横山敦郎, 橋本剛, 亘理文夫  ナノ学会大会講演予稿集  9th-  293  2011/06/02  [Not refereed][Not invited]
  
• 生体を模倣した表面化学修飾による石灰化反応の制御

  阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫, 藤井 悠平, 楠原 有紗, 大和谷 恵実, 石田 智毅, 林 大輔, 高田 知哉  北海道外科雑誌  56-  (1)  74  -75  2011/06
• Carbon Nanotube-coated Silicone as a Flexible Biomedical Material

  Nano Biomed  3-  (Special Issue)  119  2011/06  [Not refereed][Not invited]
  
• Cell proliferation on Carbon Nanotubes Coated Dishes in Different Cell Lines

  Nano Biomed  3-  (Special Issue)  78  2011/06  [Not refereed][Not invited]
  
• Cell Culture on Carbon Nanotubes Thin Films

  Nano Biomed  3-  (Special Issue)  181  2011/06  [Not refereed][Not invited]
  
• 放電プラズマ焼結による歯科用ジルコニアセラミックスの作製と機械的特性評価

  宇尾基弘, 亘理文夫, 赤坂司, 阿部薫明, 後藤孝, 木村久道, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2010-  2011
• 歯科インプラント用カーボンナノチューブコーティング陽極酸化チタンの開発と観察

  井上沙織, 宇尾基弘, 坂入正敏, 平田恵理, LEE Min-Ho, BAE Tae-Sung, 赤坂司, 亘理文夫, 横山敦郎  日本顕微鏡学会北海道支部学術講演会講演要旨集  2011-  2011
• ラジカル反応によるカルボキシル化多層カーボンナノチューブの作製と透明導電体作製への応用

  中山勝利, 阿部薫明, 林大輔, 赤坂司, 宇尾基弘, 亘理文夫, 高田知哉  化学系学協会北海道支部冬季研究発表会講演要旨集  2011-  2011
• ナノ物質の体内循環挙動の追跡とその生体親和性

  阿部薫明, 岩寺信喜, 伊藤佐智子, 赤坂司, 宇尾基弘, 八若保孝, 高田知哉, 米澤徹, 亘理文夫  ナノ学会大会講演予稿集  9th-  2011
• チタン反応性タンパク質をクロマトグラフィーと質量分析によって血清中より検出した

  久保木芳徳, 古沢利武, 佐藤正明, SUN Yongkun, 鵜沼英郎, 阿部薫明, 赤坂司, 亘理文夫, 滝田裕子, 安孫子宜光  日本バイオマテリアル学会大会予稿集  33rd-  2011
• タンパク質とチタンの反応:インプラント定着の機構解明を目指して

  久保木芳徳, 古沢利武, 佐藤正明, 孫永こん, 鵜沼英郎, 滝田裕子, 藤澤隆一, 阿部薫明, 赤坂司, 亘理文夫  北海道歯学会学術大会プログラム講演内容抄録  2011-  2011
• カーボンナノチューブのバイオ応用へ向けて

  赤坂司  北海道歯学雑誌  31-  (2)  129  -129  2010/12/15  [Not refereed][Not invited]
  
• カーボンナノチューブ薄膜上における細胞培養

  赤坂司, 橋本剛, 松岡真琴, 横山敦郎, 亘理文夫  日本バイオマテリアル学会大会予稿集  32nd-  142  -142  2010/11/29  [Not refereed][Not invited]
  
• 誘電泳動を利用したカーボンナノチューブ培養担体への細胞誘導

  松岡真琴, 赤坂司, 戸塚靖則, 亘理文夫  日本バイオマテリアル学会大会予稿集  32nd-  200  -200  2010/11/29  [Not refereed][Not invited]
  
• マイクロ・ナノ粒子の体内循環挙動の追跡と生体への影響

  岩寺 信喜, 石川 紘佑, 伊藤 佐智子, 阿部 薫明, 赤坂 司, 宇尾 基弘, 八若 保孝, 亘理 文夫, 高田 知哉, 米澤 徹  日本バイオマテリアル学会大会予稿集  32回-  323  -323  2010/11
• Cell behavior in different cell types on thin films of carbon nanotubes

  AKASAKA TSUKASA, ABE SHIGEAKI, UO MOTOHIRO, WATARI FUMIO  日本歯科理工学会誌  29-  (5)  460  -460  2010/09/20  [Not refereed][Not invited]
  
• S-PRGフィラー溶出液に浸漬したヒト歯質中ストロンチウムのXAFSによる構造解析

  宇尾 基弘, 阿部 薫明, 赤坂 司, 亘理 文夫, 中塚 稔之  日本歯科理工学会誌  29-  (5)  383  -383  2010/09
• 亜鉛錯体化合物による石灰化反応の制御

  藤井 悠平, 楠原 有紗, 大和谷 恵実, 石田 智毅, 阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫, 林 大輔, 高田 知哉  日本歯科理工学会誌  29-  (5)  438  -438  2010/09
• 有機マイクロ/ナノ粒子の体内循環挙動の追跡

  阿部 薫明, 伊藤 佐智子, 大口 郁子, 赤坂 司, 宇尾 基弘, 亘理 文夫, 林 大輔, 高田 知哉  北海道外科雑誌  55-  (1)  84  -84  2010/06
• マウスに投与したマイクロ・ナノ無機粒子の生体内分布の追跡と細胞への影響

  岩寺 信喜, 阿部 薫明, 石川 紘佑, 赤坂 司, 宇尾 基弘, 大口 郁子, 八若 保孝, 亘理 文夫, 米澤 徹  北海道外科雑誌  55-  (1)  84  -85  2010/06
• カーボンナノチューブ上の骨芽細胞、骨髄細胞の培養

  北原 浩美, 井上 農夫男, 久保木 芳徳, 赤坂 司, 宇尾 基弘, 阿部 薫明, 亘理 文夫  北海道外科雑誌  55-  (1)  85  -85  2010/06
• Influence of carbon nanotubes on biofilm growth

  AKASAKA TSUKASA, ABE SHIGEAKI, UO MOTOHIRO, WATARI FUMIO  日本歯科理工学会誌  29-  (2)  210  -210  2010/03/25  [Not refereed][Not invited]
  
• Cell adhesion to the materials treated with carbon nanotubes

  MATSUOKA MAKOTO, AKASAKA TSUKASA, TOTSUKA YASUNORI, WATARI FUMIO  日本歯科理工学会誌  29-  (2)  120  -120  2010/03/25  [Not refereed][Not invited]
  
• 微小部蛍光XAFS測定による肺胞洗浄液からの超硬合金成分の検出

  宇尾 基弘, 阿部 薫明, 赤坂 司, 亘理 文夫  日本歯科理工学会誌  29-  (2)  150  -150  2010/03
• マウス体内でのマイクロ・ナノ物質の体内動態の追跡

  岩寺 信喜, 伊藤 佐智子, 阿部 薫明, 大口 郁子, 赤坂 司, 宇尾 基弘, 八若 保孝, 亘理 文夫  日本歯科理工学会誌  29-  (2)  204  -204  2010/03
• カーボンナノチューブスカフォールド上における骨芽細胞、骨髄細胞の培養

  北原 浩美, 久保木 芳徳, 赤坂 司, 宇尾 基弘, 阿部 薫明, 亘理 文夫, 井上 農夫男  日本歯科理工学会誌  29-  (2)  207  -207  2010/03
• カーボンナノ材料のSPS焼結体による生体材料の開発

  宇尾基弘, 亘理文夫, 赤坂司, 阿部薫明, 木村久道, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2009-  2010
• 酵素モデル化合物の合成と石灰化反応制御への応用

  阿部薫明, 藤井悠平, 楠原有紗, 大和谷恵実, 石田智毅, 赤坂司, 宇尾基弘, 亘理文夫, 林大輔, 高田知哉  無機リン化学討論会講演要旨集  20th-  2010
• 細菌・細胞へのナノチューブの作用と応用

  亘理文夫, 赤坂司, 横山敦郎, 宇尾基弘  ポリマー材料フォーラム講演予稿集  19th-  2010
• 酵素モデル化合物による石灰化反応の制御

  阿部薫明, 藤井悠平, 楠原有紗, 大和谷恵実, 石田智毅, 赤坂司, 宇尾基弘, 亘理文夫, 林大輔, 高田知哉  傾斜機能材料論文集  24(CD-ROM)-  2010
• Morphology-controlled calcification (CaCO3): A donut-shape crystal growth breaking through a carbon nanotube “blanket”

  Shigeaki Abe, Tomoki Ishida, Chika Koyama, Tsukasa Akasaka, Motohiro Uo, Fumio Watari  Journal of the Australian Ceramic Society  46-  48  2010  [Not refereed][Not invited]
  
• ナノ粒子の生体反応誘発性 Biointeractive、Bioreactive特性について

  亘理 文夫, 横山 敦郎, 赤坂 司, 宇尾 基弘, 阿部 薫明, 伊藤 佐智子, 大口 郁子, 八若 保孝  日本バイオマテリアル学会大会予稿集  31回-  195  -195  2009/11
• 各種マイクロ・ナノ粒子の生体内での分布状態の追跡とその可視化

  阿部 薫明, 岩寺 信喜, 武藤 麻未, 林 大輔, 大口 郁子, 赤坂 司, 宇尾 基弘, 亘理 文夫, 高田 知哉, 米澤 徹  日本バイオマテリアル学会大会予稿集  31回-  414  -414  2009/11
• Capture of bacteria and bactericidal effect using carbon nanotubes

  AKASAKA TSUKASA, ABE SHIGEAKI, UO MOTOHIRO, WATARI FUMIO  歯科材料・器械  28-  (5)  363  -363  2009/09/10  [Not refereed][Not invited]
  
• 酵素モデル化合物の作成と石灰化反応制御への応用

  大和谷 恵実, 石田 智毅, 阿部 薫明, 大口 郁子, 赤坂 司, 宇尾 基弘, 亘理 文夫, 林 大輔, 高田 知哉  歯科材料・器械  28-  (5)  262  -262  2009/09
• 石灰化溶液によるカーボンナノチューブ上でのアパタイト様析出物の観察

  越川 高光, 久保木 芳徳, 阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫  歯科材料・器械  28-  (5)  268  -268  2009/09
• マウス由来のES細胞とiPS細胞の細胞分化に対するカーボンナノチューブの影響

  今井 弘一, 武田 昭二, 阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫  歯科材料・器械  28-  (5)  309  -309  2009/09
• 無機ケイ酸塩ナノチューブ(イモゴライト)を用いた細胞培養担体の開発

  石川 紘佑, 赤坂 司, 阿部 薫明, 宇尾 基弘, 八若 保孝, 亘理 文夫  歯科材料・器械  28-  (5)  352  -352  2009/09
• カーボンナノチューブ(CNT)に対する肝細胞の挙動

  伊藤 佐智子, 赤坂 司, 八若 保孝, 亘理 文夫  歯科材料・器械  28-  (5)  355  -355  2009/09
• カーボンナノチューブスカフォールド上における骨芽細胞、骨髄細胞の培養

  北原 浩美, 久保木 芳徳, 赤坂 司, 亘理 文夫, 井上 農夫男  歯科材料・器械  28-  (5)  356  -356  2009/09
• FRP矯正ワイヤー開発に向けた熱可塑性樹脂のナノコンポジット化

  山方 秀一, 赤坂 司, 宇尾 基弘, 飯田 順一郎, 亘理 文夫  歯科材料・器械  28-  (5)  384  -384  2009/09
• 人工酵素モデルを用いた石灰化反応の制御

  林 大輔, 高田 知哉, 阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫, 石田 智毅, 大和谷 恵美  北海道外科雑誌  54-  (1)  75  -75  2009/06
• 肝臓細胞の増殖におよぼすカーボンナノチューブの影響について

  伊藤 佐智子, 赤坂 司, 八若 保孝, 亘理 文夫  北海道外科雑誌  54-  (1)  76  -76  2009/06
• 骨芽細胞様細胞の成長に及ぼすImogoliteおよびCNTsスキャホールドの影響

  石川 紘佑, 赤坂 司, 鈴木 正哉, 亘理 文夫, 八若 保孝  小児歯科学雑誌  47-  (2)  347  -347  2009/04
• 正常肝細胞と癌肝細胞に対するカーボンナノチューブ(CNT)の影響について

  伊藤 佐智子, 赤坂 司, 亘理 文夫, 八若 保孝  小児歯科学雑誌  47-  (2)  353  -353  2009/04
• 柔軟性を持ったカーボンナノチューブによる細菌の捕捉

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  歯科材料・器械  28-  (2)  83  -83  2009/03/25  [Not refereed][Not invited]
  
• カーボンナノチューブ上の細胞培養

  亘理文夫, 赤坂司, 寺田典子, 越川高光, 宇尾基弘, 北川善政  表面技術協会講演大会講演要旨集  119th-  217  2009/03/02  [Not refereed][Not invited]
  
• Ni-Ti合金及びステンレス鋼の生体内微量溶出物のXAFSによる状態分析

  宇尾 基弘, 阿部 薫明, 赤坂 司, 亘理 文夫  歯科材料・器械  28-  (2)  39  -39  2009/03
• 肝臓細胞の増殖に及ぼすCNTの影響

  伊藤 佐智子, 赤坂 司, 八若 保孝, 亘理 文夫  歯科材料・器械  28-  (2)  46  -46  2009/03
• 大気中でのオゾン-水クラスターについての理論的研究

  阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫, 田地川 浩人  歯科材料・器械  28-  (2)  82  -82  2009/03
• PBS中におけるカーボンナノチューブ表面でのアパタイト様化合物の形成

  越川 高光, 宇尾 基弘, 赤坂 司, 久保木 芳徳, 亘理 文夫  歯科材料・器械  28-  (2)  113  -113  2009/03
• 亜鉛-イミダゾール錯体を持つ酵素モデル化合物による石灰化反応の制御

  阿部薫明, 林大輔, 大和谷恵実, 石田智毅, 赤坂司, 宇尾基弘, 亘理文夫, 高田知哉  錯体化学討論会講演要旨集  59th-  2009
• PBS中におけるカーボンナノチューブ表面でのアパタイトの形成

  越川高光, 宇尾基弘, 赤坂司, 久保木芳徳, 亘理文夫  化学系学協会北海道支部冬季研究発表会講演要旨集  2009-  2009
• ナノ微粒子の体内動態可視化法の開発 生体に投与した有機・無機粒子の体内動態のイメージングに関する研究

  亘理文夫, 阿部薫明, 久保木芳徳, 森田学, 八若保孝, 宇尾基弘, 赤坂司, 江崎光恵, 岩寺信喜  ナノ微粒子の体内動態可視化法の開発 平成18-20年度 総合研究報告書  2009
• ナノ微粒子の体内動態可視化法の開発 生体に投与した有機・無機粒子の体内動態のイメージングに関する研究

  亘理文夫, 阿部薫明, 久保木芳徳, 八若保孝, 宇尾基弘, 赤坂司, 岩寺信喜  ナノ微粒子の体内動態可視化法の開発 平成20年度 総括・分担研究報告書  2009
• ナノ微粒子の体内動態可視化法の開発 カーボンナノチューブが細胞に及ぼす影響に関する研究

  戸塚靖則, 高師則行, 赤坂司, 松岡真琴, 亘理文夫  ナノ微粒子の体内動態可視化法の開発 平成20年度 総括・分担研究報告書  2009
• ナノ微粒子の体内動態可視化法の開発 細胞培養におけるカーボンナノチューブ膜の影響

  亘理文夫, 宇尾基弘, 赤坂司, 阿部勲明  ナノ微粒子の体内動態可視化法の開発 平成20年度 総括・分担研究報告書  2009
• Application of flake shaped glass filler containing polycarbonate for non-clasp partial denture

  佐々木朗子, 宇尾基弘, 岩崎佳治, 阿部薫明, 赤坂司, 亘理文夫  歯科材料・器械  28-  (5)  2009
• ナノ微粒子の体内動態可視化法の開発 ナノチューブ,ナノ微粒子,マイクロ微粒子の組織反応性とバイオ応用に関する研究

  戸塚靖則, 高師則行, 赤坂司, 松岡真琴, 亘理文夫  ナノ微粒子の体内動態可視化法の開発 平成18-20年度 総合研究報告書  2009
• ナノ微粒子の体内動態可視化法の開発 フラーレンマーカーの合成およびカーボンナノチューブのバイオ応用

  亘理文夫, 宇尾基弘, 赤坂司, 阿部勲明  ナノ微粒子の体内動態可視化法の開発 平成18-20年度 総合研究報告書  2009
• Culturing osteoblast-like cells on a carbon nanotube-coated dish. Nano Biomedicine

  MATSUOKA Makoto, AKASAKA Tsukasa, HASHIMOTO Takeshi, TOTSUKA Yasunori, WATARI Fumio  Nano Biomedicine  1-  (1)  17  -25  2009  [Not refereed][Not invited]
  
• Controlled calcification using polyanionic macromolecules with an active reaction center analogue of carbonic anhydrase

  Shigeaki Abe, Tomoki Ishida, Emi Yamatoya, Daisuke Hayashi, Tsukasa Akasaka, Motohiro Uo, Fumio Watari, Tomoya Takada  Nano Biomedicine  1-  (1)  51  -58  2009  [Not refereed][Not invited]
  
• Internal distribution of several inorganic microparticles in mice

  Shigeaki Abe, Chika Koyama, Tsukasa Akasaka, Motohiro Uo, Yoshinori Kuboki, Fumio Watari  BIOCERAMICS 21  396-398-  539  -542  2009  [Not refereed][Not invited]
   

  Internal distributions of several inorganic microparticles administered into the tail vein of mice were determined using a Scanning X-ray analytical microscopy and energy-dispersed X-ray spectroscopy. After administration through the tail vein of mice, the particles circulated by blood flow then reach some organs and temporally remained. In this study, we determined that the distribution behaviors in body depend upon the chemical species and the size.
• 単層カーボンナノチューブ透明導電性薄膜上での細胞培養

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  歯科材料・器械  27-  (5)  392  -392  2008/09/05  [Not refereed][Not invited]
  
• 高い細胞接着性と電気伝導性を併せ持つ生体再建材料の開発

  松岡真琴, 赤坂司, 戸塚靖則, 亘理文夫  歯科材料・器械  27-  (5)  358  -358  2008/09/05  [Not refereed][Not invited]
  
• ガラスフレークフィラーを用いた高流動性歯科用コンポジットレジンの開発

  宇尾 基弘, 阿部 薫明, 赤坂 司, 亘理 文夫  歯科材料・器械  27-  (5)  331  -331  2008/09
• カーボンナノチューブスキャフォルドの性能に対するナノ構造の効果(Effect of Nanostructure on the Performance of Carbon Nanotubes Scaffolds)

  リ・シャオミン, 宇尾 基弘, 阿部 薫明, 赤坂 司, 亘理 文夫  歯科材料・器械  27-  (5)  427  -427  2008/09
• ケイ酸塩ナノチューブ(イモゴライト)上での骨芽細胞培養

  石川 紘佑, 赤坂 司, 八若 保孝, 亘理 文夫  歯科材料・器械  27-  (5)  433  -433  2008/09
• バイオミメティクポリマーによる石灰化反応の制御

  石田 智毅, 阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫  歯科材料・器械  27-  (5)  438  -438  2008/09
• 単層カーボンナノチューブ透明導電性薄膜での骨芽細胞様細胞の培養

  赤坂司, 横山敦郎, 松岡真琴, 阿部薫明, 宇尾基弘, 亘理文夫, 橋本剛  北海道外科雑誌  53-  (1)  122  -122  2008/06/20  [Not refereed][Not invited]
  
• マウス体内での有機・無機粒子の体内循環挙動の追跡

  阿部 薫明, 江崎 光恵, 赤坂 司, 宇尾 基弘, 森田 学, 亘理 文夫, 小山 千佳, Rosca Iosif Danel, 久保木 芳徳  北海道外科雑誌  53-  (1)  122  -122  2008/06
• ヤギシャンク骨欠損モデルを用いたキチン質繊維強化とナノアパタイト/コラーゲンコンポジットの骨修復特性評価

  Li Xiaoming, Feng Qingling, Cui Fuzhai, 宇尾 基弘, 赤坂 司, 亘理 文夫  北海道外科雑誌  53-  (1)  122  -123  2008/06
• ナノマテリアルの評価手法に関する研究の進展 組織反応と体内動態の可視化研究について

  亘理 文夫, 阿部 薫明, 宇尾 基弘, 江崎 光恵, 森田 学, 平田 恵理, 横山 敦郎, 赤坂 司, 韮澤 崇, 佐藤 義倫, 田路 和幸  The Journal of Toxicological Sciences  33-  (Suppl.)  S37  -S37  2008/06
• 単層カーボンナノチューブ透明導電性薄膜上での骨芽細胞様細胞の培養

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  歯科材料・器械  27-  (2)  168  -168  2008/03/31  [Not refereed][Not invited]
  
• シルクによる繊維強化レジンの作製とその機械的特性

  宇尾 基弘, 阿部 薫明, 赤坂 司, 亘理 文夫  歯科材料・器械  27-  (2)  125  -125  2008/03
• 骨関連細胞への生体材料の微細構造のin vitroでの影響(Effect of microstructures of biomaterials on bone-related cells in vitro)

  リ・シャオミン, 宇尾 基弘, 赤坂 司, 亘理 文夫  歯科材料・器械  27-  (2)  195  -195  2008/03
• 各種マイクロ・ナノ粒子の生体内での分布状態の追跡とその可視化

  阿部 薫明, 江崎 光恵, 赤坂 司, 宇尾 基弘, 久保木 芳徳, 亘理 文夫  歯科材料・器械  27-  (2)  231  -231  2008/03
• ナノチューブ系新素材をベースとした生体材料の放電プラズマ焼結

  亘理文夫, 宇尾基弘, 赤坂司, 阿部薫明, 木村久道, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2007-  2008
• ナノ微粒子の体内動態可視化法の開発 生体に投与した有機・無機粒子の体内動態のイメージング

  亘理文夫, 阿部薫明, 森田学, 江崎光恵, 宇尾基弘, 赤坂司, 久保木芳徳  ナノ微粒子の体内動態可視化法の開発 平成19年度 総括・分担研究報告書  2008
• ナノ微粒子の体内動態可視化法の開発 細胞培養におけるカーボンナノチューブ膜の影響

  亘理文夫, 宇尾基弘, 赤坂司, 阿部薫明  ナノ微粒子の体内動態可視化法の開発 平成19年度 総括・分担研究報告書  2008
• 正常および癌肝細胞培養に対するCNTの影響の相違

  伊藤佐智子, 赤坂司, 八若保孝, 亘理文夫  歯科材料・器械  27-  (5)  2008
• ナノ微粒子の体内動態可視化法の開発 カーボンナノチューブをコートしたシリコーンラバーでの細胞接着に関する研究

  戸塚靖則, 高師則行, 赤坂司, 松岡真琴, 亘理文夫  ナノ微粒子の体内動態可視化法の開発 平成19年度 総括・分担研究報告書  2008
• 生物学的反応プロセスによるナノ微粒子の機能性転換

  亘理 文夫, 横山 敦郎, Gelinsky M., 廖 素三, 井上 沙織, 赤坂 司  日本バイオマテリアル学会大会予稿集  29回-  220  -220  2007/11
• 有機・無機微粒子の体内動態イメージング法の検討

  阿部 薫明, 小山 千佳, Rosca Iosif Danel, 赤坂 司, 宇尾 基弘, 久保木 芳徳, 亘理 文夫  日本バイオマテリアル学会大会予稿集  29回-  409  -409  2007/11
• カーボンナノチューブのアパタイト修飾

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  無機リン化学討論会講演予稿集  17th-  104  -105  2007/10/02  [Not refereed][Not invited]
  
• B28 Cell Culture on a Imogolite Scaffold

  Ishikawa Kosuke, Akasaka Tsukasa, Yawaka Yasutaka, Suzuki Masaya, Watari Fumio  粘土科学討論会講演要旨集  (51)  144  -145  2007/09/12
• 人工複合糖質高分子によるStreptococcus mutansの増殖阻害

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  北海道外科雑誌  52-  (1)  87  -87  2007/06/20  [Not refereed][Not invited]
  
• 耐磨耗性インプラント材料のためのチタンへの表面炭化物形成

  朱 禹赫, 宇尾 基弘, 赤坂 司, 亘理 文夫  北海道外科雑誌  52-  (1)  86  -86  2007/06
• 金属微粒子の体内動態の可視化と生体組織への影響

  阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫, 小山 千佳, 久保木 芳徳  北海道外科雑誌  52-  (1)  87  -87  2007/06
• 人工複合糖質高分子によるStreptococcus mutansの増殖阻害機構

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  歯科材料・器械  26-  (2)  245  -245  2007/04/25  [Not refereed][Not invited]
  
• 各種金属微粒子の体内動態のイメージング

  阿部 薫明, 赤坂 司, 宇尾 基弘, 久保木 芳徳, 亘理 文夫  歯科材料・器械  26-  (2)  241  -241  2007/04
• カーボンナノチューブのバイオ応用

  赤坂司, 青木尚史, 横山敦郎, 阿部薫明, 宇尾基弘, 亘理文夫  日本顕微鏡学会北海道支部学術講演会プログラム・予稿集  2006-  17  2007/02  [Not refereed][Not invited]
  
• X線分析顕微鏡及びEDSを用いた生体内金属元素の分布分析

  宇尾基弘, 阿部薫明, 赤坂司, 亘理文夫  日本顕微鏡学会北海道支部学術講演会プログラム・予稿集  2006-  2007
• 蛍光エックス線顕微鏡を用いたナノマテリアルの体内動態の可視化

  阿部薫明, 小山千佳, 赤坂司, 宇尾基弘, 久保木芳徳, 亘理文夫  三学協会北海道支部研究発表会講演要旨集  2007-  2007
• ナノチューブ系新素材をベースとした生体材料の放電プラズマ焼結

  亘理文夫, 宇尾基弘, 赤坂司, 阿部薫明, ZHU YH., WANG W., 横山敦郎, 木村久道, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2006-  2007
• Na₂O-CaO-P₂O₅系水溶性ガラスの作製と細胞毒性評価

  宇尾基弘, 赤坂司, 阿部薫明, 亘理文夫  無機リン化学討論会講演要旨集  17th-  2007
• 単分散カーボンナノチューブを用いたハイドロキシアパタイト合成

  赤木健太郎, 赤坂司, 亘理文夫, 古月文志  日本化学会北海道支部研究発表会講演要旨集  2007-  2007
• カーボンナノチューブ膜の作製と物性

  宇尾基弘, 阿部薫明, 赤坂司, 亘理文夫  歯科材料・器械  26-  (2)  2007
• Handbook of Biomeneralization -Medical and Clinical Aspects

  Fumio Watari, Kazuchika Tamura, Atsuro Yokoyama, Ken-ichiro Shibata, Tsukasa Akasaka, Bunshi Fugetsu, Kiyotaka Asakura, Motohiro Uo, Yasunori Totsuka, Yoshinori Sato, Kazuyuki Tohji  127  -144  2007  [Not refereed][Not invited]
  
• BTC(Bench to Clinic)研究室から臨床へ 口腔内における糖鎖の働き

  赤坂司, 亘理文夫  DE  (159)  26  -28  2006/10/25  [Not refereed][Not invited]
  
• 人工複合糖質高分子によるStreptococcus mutansの増殖阻害

  赤坂司, 阿部薫明, 宇尾基弘, 亘理文夫  歯科材料・器械  25-  (5)  336  -336  2006/10/16  [Not refereed][Not invited]
  
• バイオ応用へ向けた機能性フラーレンの作製

  阿部 薫明, 赤坂 司, 宇尾 基弘, 亘理 文夫  歯科材料・器械  25-  (5)  360  -360  2006/10
• 人工複合糖質高分子によるStreptococcus mutansの発育阻害

  赤坂司, 宇尾基弘, 亘理文夫  フラーレン・ナノチューブ総合シンポジウム講演要旨集  31st-  106  2006/07/12  [Not refereed][Not invited]
  
• 糖鎖工学と歯学

  赤坂司, 宇尾基弘, 亘理文夫  北海道歯学雑誌  27-  (1)  41  -44  2006/06/15  [Not refereed][Not invited]
  
• 歯科用合金粉末を含む口腔組織中のセレンの分布及び状態分析

  宇尾 基弘, 赤坂 司, 亘理 文夫  歯科材料・器械  25-  (2)  191  -191  2006/04
• 放電プラズマ焼結法により作製したインプラント用カーボンナノチューブ固化体の機械的性質および生体適合性

  WANG W., 横山敦郎, 宇尾基弘, 赤坂司, 亘理文夫, 木村久道, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2005-  2006
• 歯科用合金を含む口腔組織中のセレンの分布と状態分析

  宇尾基弘, 赤坂司, 亘理文夫, 朝倉清高  日本顕微鏡学会北海道支部学術講演会プログラム・予稿集  2005 (Web)-  2006
• XAFSを用いた金属インプラント周囲組織中の微量金属元素の状態分析

  宇尾基弘, 赤坂司, 亘理文夫, 朝倉清高, 横山敦郎  北海道外科雑誌  51-  (1)  2006
• 表面炭化したチタンの生体材料特性

  ZHU YH., WANG W., 宇尾基弘, 赤坂司, 菅原敏, 横山敦郎, 亘理文夫  歯科材料・器械  25-  (2)  2006
• Comparison of Morphology and behavior of carbon nanotubes and asbestos

  F. Watari, M. Inoue, T. Akasaka, N. Sakaguchi, H. Ichinose, M. Uo  Proceedings of 6th Asian BioCeramics Symposium 2006  142  -145  2006  [Not refereed][Not invited]
  
• 細菌付着阻害剤へ向けた糖鎖化合物の調製

  赤坂司, 宇尾基弘, 菅原敏, 亘理文夫  歯科材料・器械  24-  (5)  348  -348  2005/09/05  [Not refereed][Not invited]
  
• カーボンナノチューブを用いた細胞培養用スキャホールドの開発

  青木尚史, 横山敦郎, 赤坂司, 宇尾基弘, 亘理文夫  歯科材料・器械  24-  (5)  281  -281  2005/09/05  [Not refereed][Not invited]
  
• 炭化炭素雰囲気中で表面炭化したチタンの耐磨耗性生体材料特性

  朱 禹赫, 下妻 光夫, 宇尾 基弘, 赤坂 司, 菅原 敏, 王 蔚, 亘理 文夫  歯科材料・器械  24-  (5)  292  -292  2005/09
• 希土類含有カーボンナノカプセルの物性と細胞毒性

  宇尾 基弘, 赤坂 司, 亘理 文夫, 横山 敦郎, 田村 一央, 戸塚 靖則  歯科材料・器械  24-  (5)  350  -350  2005/09
• コバルトを添加した試作歯科用金合金の諸特性

  石 典芳, 岩崎 佳治, 菅原 敏, 朱 禹赫, 赤坂 司, 宇尾 基弘, 亘理 文夫  歯科材料・器械  24-  (5)  363  -363  2005/09
• 純チタンと歯科用貴金属合金のレーザー溶接

  岩崎 佳治, 大川 昭治, 赤坂 司, 宇尾 基弘, 亘理 文夫  日本歯技  2003-  (434)  33  -40  2005/07  [Not refereed][Not invited]
  
• カーボンナノチューブの細胞培養用担体への応用

  青木尚史, 横山敦郎, 赤坂司, 宇尾基弘, 亘理文夫  北海道外科雑誌  50-  (1)  78  -78  2005/06/20  [Not refereed][Not invited]
  
• バイオミメティックコーティングを用いたカーボンナノチューブの表面修飾

  赤坂司, 宇尾基弘, 亘理文夫  北海道外科雑誌  50-  (1)  78  -78  2005/06/20  [Not refereed][Not invited]
  
• 生体用カーボンナノチューブ焼結体の作製と特性

  王 蔚, 近藤 英臣, 横山 敦朗, 宇尾 基弘, 大川 昭治, 赤坂 司, 菅原 敏, 亘理 文夫, 大森 守  北海道外科雑誌  50-  (1)  77  -78  2005/06
• 蛍光性を持つコンポジットレジン用ガラスフィラーに関する研究

  宇尾 基弘, 赤坂 司, 亘理 文夫, 谷 和俊, 森田 学  北海道外科雑誌  50-  (1)  78  -79  2005/06
• 焼結したカーボンナノチューブ固化体の生体適合性

  王 蔚, 横山 敦郎, 廖 素三, 宇尾 基弘, 赤坂 司, 大川 昭治, 菅原 敏, 亘理 文夫, 大森 守  歯科材料・器械  24-  (2)  135  -135  2005/04
• 純チタンと歯科用貴金属合金のレーザー溶接

  岩崎佳治, 岩崎佳治, 大川昭治, 赤坂司, 宇尾基弘, 亘理文夫  日本歯技  (434)  2005
• 難焼結性生体材料の放電プラズマ焼結とその評価-放電プラズマ焼結を用いたカーボンナノチューブ固化体の製作とその評価-

  WANG W., 横山敦郎, LIAO S. S., 宇尾基弘, 赤坂司, 亘理文夫, 大森守, 大久保昭  東北大学金属材料研究所金属ガラス総合研究センター共同利用研究報告書  2004-  2005
• チタンと歯科用貴金属合金の開先形態におけるレーザー溶接

  岩崎 佳治, 大川 昭治, 宇尾 基弘, 赤坂 司, 中田 久夫, 朝田 英哉, 亘理 文夫  日本歯科技工学会雑誌  25-  (2)  234  -234  2004/12
• 複合糖質高分子によるカーボンナノチューブの表面修飾

  赤坂司, 亘理文夫  日本バイオマテリアル学会シンポジウム予稿集  2004-  134  2004/11/15  [Not refereed][Not invited]
  
• カーボンナノチューブの生体材料への応用 細胞培養用担体の開発

  青木 尚史, 横山 敦郎, 川崎 貴生, 野田坂 圭伸, 赤坂 司, 宇尾 基弘, 亘理 文夫  日本補綴歯科学会雑誌  48-  (112回特別)  151  -151  2004/10
• カーボンナノチューブの生体材料への応用―細胞培養用担体の開発―

  青木尚史, 横山敦郎, 川崎貴生, 野田坂圭伸, 赤坂司, 宇尾基弘, 亘理文夫  日本補綴歯科学会学術大会プログラム・抄録集  112th-  151  2004/10  [Not refereed][Not invited]
  
• バイオミメティックコーティングを用いたカーボンナノチューブの表面修飾

  赤坂司, 宇尾基弘, 大川昭治, 菅原敏, 亘理文夫  歯科材料・器械  23-  (5)  392  -392  2004/09/10  [Not refereed][Not invited]
  
• カーボンナノチューブ固化体の焼結と生体適合性

  王 蔚, 近藤 英臣, 横山 敦郎, 川崎 貴生, 宇尾 基弘, 大川 昭治, 赤坂 司, 菅原 敏, 亘理 文夫, 大森 守  歯科材料・器械  23-  (5)  330  -330  2004/09
• チタンと貴金属とのレーザー溶接部の元素分布

  岩崎 佳治, 大川 昭治, 宇尾 基弘, 赤坂 司, 菅原 敏, 亘理 文夫  歯科材料・器械  23-  (5)  352  -352  2004/09
• 糖鎖によるカーボンナノチューブの表面修飾

  赤坂司, 佐藤義倫, 田路和幸, 亘理文夫  傾斜機能材料論文集  2003-  116  -121  2004/07/15  [Not refereed][Not invited]
  
• 糖鎖によるカーボンナノチューブの表面修飾

  赤坂司, 亘理文夫, 佐藤義倫, 田路和幸  北海道外科雑誌  49-  (1)  100  -101  2004/06/20  [Not refereed][Not invited]
  
• X線分析顕微鏡の生体内金属材料及び周囲組織分析への応用

  宇尾 基弘, 赤坂 司, Daniel Rosca Iosif, 亘理 文夫  北海道外科雑誌  49-  (1)  98  -98  2004/06
• ナノ・マイクロ微粒子の生体への影響 歯科診療で発生する微粒子の細胞への影響

  田村 一央, 高師 則行, ロスカ・イオシフ, 赤坂 司, 渥美 崇, 佐藤 義倫, 宇尾 基弘, 戸塚 靖則, 亘理 文夫  歯科材料・器械  23-  (2)  129  -129  2004/03
• カーボンナノチューブ焼結体の作製とその特性

  王 蔚, 近藤 英臣, 横山 敦郎, 川崎 貴生, 宇尾 基弘, 大川 昭治, 赤坂 司, 菅原 敏, 亘理 文夫, 大森 守  歯科材料・器械  23-  (2)  133  -133  2004/03
• 蛍光性を持つコンポジットレジン用ガラスフィラーに関する研究

  宇尾 基弘, 赤坂 司, Daniel Rosca Iosif, 大川 昭治, 菅原 敏, 亘理 文夫, 谷 和俊, 森田 学  歯科材料・器械  23-  (2)  135  -135  2004/03
• X線分析顕微鏡の生体内金属材料及び周囲組織分析への応用

  宇尾基弘, 赤坂司, DANIEL R I, 亘理文夫  傾斜機能材料論文集  2003-  2004
• Tissue reaction to nanotube, nanoparticle, and microparticle, and their biological application. Preparation and evaluation of composite material using carbon nanotube.

  宇尾基弘, 赤坂司, 亘理文夫, 横山敦郎, 川崎貴夫, 田村一央, 佐藤義倫, 田路和幸, 大森守  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  2004
• Tissue reaction to nanotube, nanoparticle, and microparticle, and their biological application. Preparation and evaluation of composite material using carbon nanotube: biotoxicity of carbon nanocapsule.

  宇尾基弘, 赤坂司, 横山敦郎, 川崎貴夫, 田村一央, 戸塚靖則, 佐藤義倫, 田路和幸, 大森守  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  2004
• The tissue reaction of nanotube, nanoparticle, and microparticle, and biological application. Production and evaluation of composite material: biotoxicity of carbon nanocapsules.

  亘理文夫, 宇尾基弘, 赤坂司, ダニエルロスカ イオシフ, 田村一央  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  2004
• The tissue reaction of nanotube, nanoparticle, and microparticle, and biological application. Functionalization of carbon nanotube.

  亘理文夫, 赤坂司, 宇尾基弘, 佐々木紘子, 青木尚志, 田村一央  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  2004
• 乾式合成法による窒化チタン/アパタイト系傾斜機能型インプラントの作製と評価

  近藤英臣, 横山敦郎, 川崎貴生, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  歯科材料・器械  23-  (2)  2004
• Tissue reaction to nanotube, nanoparticle, and microparticle, and their biological application. Application of carbon nanotube to biomaterial.

  横山敦郎, 山本悟, 赤坂司, 古月文志, 佐藤義倫, 田路和幸, 小野木伯薫, 橋田俊之, 大森守  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  2004
• 象牙質へのレジンモノマーの拡散と強化の可能性

  神島奈穂子, 大畑昇, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  歯科材料・器械  23-  (2)  2004
• XAFSを用いた金属インプラント周囲組織の分析

  宇尾基弘, 赤坂司, 亘理文夫, 横山敦郎, 田村一央, 戸塚靖則  歯科材料・器械  23-  (5)  2004
• The tissue reaction of nanotube, nanoparticle, and microparticle, and biological application. Functionalization of carbon nanotube.

  AKASAKA TSUKASA, YOKOYAMA ATSURO, TAMURA KAZUCHIKA, UO MOTOHIRO, WATARI FUMIO, SATO YOSHITSUGU, TAJI KAZUYUKI  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  518  -531  2004  [Not refereed][Not invited]
  
• Tissue reaction to nanotube, nanoparticle, and microparticle, and their biological application. Functionalization of carbon nanotube and its biological application. Modification by carbohydrate compounds.

  AKASAKA TSUKASA, SASAKI KOKO, AOKI HISASHI, YOKOYAMA ATSURO, TAMURA KAZUCHIKA, UO MOTOHIRO, WATARI FUMIO, SATO YOSHITSUGU, TAJI KAZUYUKI  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  628  -638  2004  [Not refereed][Not invited]
  
• Tissue reaction to nanotube, nanoparticle, and microparticle, and their biological application. Functionalization of carbon nanotube and its biological application. Plasticity of single-walled carbon nanotube.

  SASAKI KOKO, AOKI HISASHI, YOKOYAMA ATSURO, KAWASAKI TAKAO, AKASAKA TSUKASA, UO MOTOHIRO, WATARI FUMIO, SATO YOSHITSUGU, TAJI KAZUYUKI  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成15年度 総括・分担研究報告書  665  -667  2004  [Not refereed][Not invited]
  
• カーボンナノチューブを用いた培養基材の表面改質

  赤坂司, 田村一央, 亘理文夫  日本バイオマテリアル学会大会予稿集  25th-  215  2003/12/16  [Not refereed][Not invited]
  
• チタンと歯科用貴金属合金のレーザー溶接

  岩崎 佳治, 大川 昭治, 宇尾 基弘, 赤坂 司, 中田 久夫, 朝田 英哉, 亘理 文夫  日本歯科技工学会雑誌  24-  (2)  282  -282  2003/12
• ナノ/ミクロ粒子に対する病理生物学的反応(Pathobiological response to nano/micro particles)

  田村 一央, 高師 則行, 宇尾 基弘, ロスカイオシフ, 赤坂 司, 戸塚 靖則, 亘理 文夫  歯科基礎医学会雑誌  45-  (5)  275  -275  2003/09
• 象牙質へのカーボンナノチューブ吸着による表面改質

  赤坂司, 宇尾基弘, 大川昭治, 菅原敏, 亘理文夫  歯科材料・器械  22-  (5)  397  -397  2003/08/25  [Not refereed][Not invited]
  
• チタンと歯科用貴金属合金の開先形態におけるレーザー溶接

  岩崎 佳治, 大川 昭治, 宇尾 基弘, 赤坂 司, 菅原 敏, 亘理 文夫  歯科材料・器械  22-  (5)  403  -403  2003/08
• 人工複合糖質高分子によるカーボンナノチューブの表面修飾

  赤坂司, 宇尾基弘, 田路和幸, 亘理文夫  日本糖質学会年会要旨集  24th-  125  2003/07/03  [Not refereed][Not invited]
  
• 放電プラズマ焼結法で作製した窒化チタン/アパタイト系傾斜機能型インプラントの物性と生体適合性の評価

  近藤 英臣, 横山 敦郎, 川崎 貴生, 宇尾 基弘, 大川 昭治, 菅原 敏, 赤坂 司, 亘理 文夫  歯科材料・器械  22-  (2)  54  -54  2003/03
• カーボンナノチューブとナノ・マイクロ微粒子に対する生体反応

  田村 一央, 高師 則行, 赤坂 司, 宇尾 基弘, 大川 昭治, 菅原 敏, 古月 文志, 田路 和幸, 戸塚 靖則, 亘理 文夫  歯科材料・器械  22-  (2)  57  -57  2003/03
• 歯質とレジン及びポーセレン修復部の識別に関する分光学的研究

  谷 和俊, 森田 学, 宇尾 基弘, 大川 昭治, 赤坂 司, 菅原 敏, 亘理 文夫  歯科材料・器械  22-  (2)  80  -80  2003/03
• チタンと歯科用貴金属合金のレーザー溶接による接合

  岩崎 佳治, 大川 昭治, 宇尾 基弘, 赤坂 司, 菅原 敏, 亘理 文夫  歯科材料・器械  22-  (2)  122  -122  2003/03
• Nd:YAG,Er:YAG,CO2レーザー照射した歯質の表面形態観察とスペクトル分析

  ヤマダ・マギダ・キヨコ, 宇尾 基弘, 大川 昭治, 赤坂 司, 菅原 敏, 亘理 文夫  歯科材料・器械  22-  (2)  124  -124  2003/03
• 各種レジンモノマーの歯質への拡散の測定

  神島 奈穂子, 佐藤 範幸, 大畑 昇, 宇尾 基弘, 大川 昭治, 赤坂 司, 菅原 敏, 亘理 文夫  歯科材料・器械  22-  (2)  131  -131  2003/03
• チタンと歯科用貴金属合金のレーザー溶接による接合

  岩崎佳治, 大川昭治, 宇尾基弘, 赤坂司, 菅原敏, 亘理文夫  日本歯科理工学会学術講演会講演集  41st-  2003
• ナノ・マイクロ微粒子バイオマテリアルの組織障害の機序

  田村一央, 高師則行, 赤坂司, IOSIF R, 宇尾基弘, 戸塚靖則, 亘理文夫  日本バイオマテリアル学会大会予稿集  25th-  2003
• Nd:YAG,Er:YAG,CO₂レーザー照射した歯質の表面形態観察とスペクトル分析

  ヤマダ(マギダ) キヨコ, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  日本歯科理工学会学術講演会講演集  41st-  2003
• 各種レジンモノマーの歯質への拡散の測定

  神島奈穂子, 佐藤範幸, 大畑昇, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  日本歯科理工学会学術講演会講演集  41st-  2003
• 歯質とレジン及びポーセレン修復部の識別に関する分光学的研究

  谷和俊, 森田学, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  日本歯科理工学会学術講演会講演集  41st-  2003
• 歯根膜由来細胞に対する微粒子の影響

  田村一央, 高師則行, 赤坂司, 宇尾基弘, 大川昭治, 菅原敏, 戸塚靖則, 亘理文夫  歯科材料・器械  22-  (5)  2003
• 乾式合成法によるTi-HAP複合体の作製と評価

  近藤英臣, 横山敦郎, 川崎貴生, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  歯科材料・器械  22-  (5)  2003
• 象牙質への各種レジンモノマーの浸透度の比較

  神島奈穂子, 佐藤範幸, 大畑昇, 宇尾基弘, 大川昭治, 赤坂司, 菅原敏, 亘理文夫  歯科材料・器械  22-  (5)  2003
• 放電プラズマ焼結法で作製した窒化チタン/アパタイト系傾斜機能型インプラントの物性と生体適合性の評価

  近藤英臣, 横山敦郎, 川崎貴生, 宇尾基弘, 大川昭冶, 菅原敏, 赤坂司, 亘理文夫  日本歯科理工学会学術講演会講演集  41st-  2003
• カーボンナノチューブとナノ・マイクロ微粒子に対する生体反応

  田村一央, 高師則行, 赤坂司, 宇尾基弘, 菅原敏, 古月文志, 田路和幸, 戸塚靖則, 亘理文夫  日本歯科理工学会学術講演会講演集  41st-  2003
• Tissue reactivity of nanotubes, nanoparticles, and microparticles, and their biological applications. Functionalization of carbon nanotubes and biological application.

  亘理文夫, 赤坂司, 宇尾基弘  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成14年度 総括・分担研究報告書  2003
• Tissue reactivity of nanotubes, nanoparticles, and microparticles, and their biological applications. Functionalization of carbon nanotubes, and biological application.

  AKASAKA TSUKASA, UO MOTOHIRO, WATARI FUMIO, TOJI KAZUYUKI  ナノチューブ、ナノ微粒子、マイクロ微粒子の組織反応性とバイオ応用 平成14年度 総括・分担研究報告書  424  -425  2003  [Not refereed][Not invited]
  
• 北海道産カラマツ由来多糖アラビノガラクタンの構造解析

  赤坂司, 前川宜彦  日本糖質学会年会要旨集  23rd-  113  2002/07/25  [Not refereed][Not invited]
  
• 北海道産カラマツ由来多糖アラビノガラクタンの構造解析

  赤坂司, 前川宜彦  日本木材学会北海道支部講演集  (33)  57  -60  2001/10/15  [Not refereed][Not invited]
  
• プラスミド‐糖鎖コンジュゲートを用いた遺伝子発現制御系の構築

  林克洋, 赤坂司, 松浦和則, 小林一清  高分子学会予稿集  50-  (5)  1005  2001/05/07  [Not refereed][Not invited]
  
• DNA‐糖コンジュゲートの創成

  松浦和則, 赤坂司, 日比野美紀, 山田喜直, 小林一清  日本糖質学会年会要旨集  21st-  51  2000/06/30  [Not refereed][Not invited]
  
• ジアゾカップリング法によるDNA‐シクロデキストリンコンジュゲートの合成と分子認識

  林克洋, 赤坂司, 松浦和則, 小林一清  高分子学会予稿集  49-  (5)  871  2000/05/12  [Not refereed][Not invited]
  
• Preparation of block-type of oligoDNA-glycopolymer conjugates and their characterization.

  AKASAKA TSUKASA, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO  日本化学会講演予稿集  78th-  (2)  827  2000/03/15  [Not refereed][Not invited]
  
• Facil Synthesis of Stable and Lectin-Recognizable DNA-Carbohydrate conjugates via Diazo Coupling (jointly worked)

  Bioconjugate Chem  11, 202-211-  2000  [Not refereed][Not invited]
  
• DNAハイブリダイゼーションを利用した糖クラスターの構築

  松浦和則, 日比野美紀, 山田喜直, 赤坂司, 小林一清  高分子学会予稿集  49-  (5)  2000
• Preparation of block type of oligoDNA-glycopolymer conjugates.

  AKASAKA TSUKASA, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO  日本化学会講演予稿集  77th-  75  1999/09/10  [Not refereed][Not invited]
  
• Preparation of Plasmid-Carbohydrate Conjugates and their Characterizations.

  AKASAKA TSUKASA, MORI KOICHI, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO  高分子学会予稿集  48-  (4)  766  1999/05/12  [Not refereed][Not invited]
  
• Preparation of Plasmid-Carbohydrate Conjugates and their Characterizations.

  AKASAKA TSUKASA, MORI KOICHI, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO, EMI NOBUHIKO  日本化学会講演予稿集  76th-  (2)  761  1999/03/15  [Not refereed][Not invited]
  
• Synthesis of DNA-carbohydrate conjugate via diazocoupling: A new class of modified DNA with enhanced stability and lectin-recognition ability

  K Matsuura, T Akasaka, M Hibino, K Kobayashi  CHEMISTRY LETTERS  3, 247-248-  (3)  247  -248  1999/03  [Not refereed][Not invited]
   

  Salmon testes DNA was treated with a diazonium salt connected to N-beta-lactoside via a spacer chain to yield a diazo coupling product with a degree of substitution of 0.14. The DNA-lactose conjugate kept a typical B-type conformation similar to native DNA, and showed higher melting temperature and stronger nuclease resistance than native DNA. The conjugate was found to acquire a strong binding affinity to galactose-specific lectin RCA(120).
• Synthesis of DNA-carbohydrate conjugate via diazocoupling: A new class of modified DNA with enhanced stability and lectin-recognition ability

  K Matsuura, T Akasaka, M Hibino, K Kobayashi  CHEMISTRY LETTERS  (3)  247  -248  1999/03  [Not refereed][Not invited]
   

  Salmon testes DNA was treated with a diazonium salt connected to N-beta-lactoside via a spacer chain to yield a diazo coupling product with a degree of substitution of 0.14. The DNA-lactose conjugate kept a typical B-type conformation similar to native DNA, and showed higher melting temperature and stronger nuclease resistance than native DNA. The conjugate was found to acquire a strong binding affinity to galactose-specific lectin RCA(120).
• Synthesis and sspecific biological activities of polymethacrylate derivative having sulfated oligosaccharide side chains(jointly worked)

  J.Poly.Sci.A: Polym.Chem  37, 789-800-  1999  [Not refereed][Not invited]
  
• DNAを基本骨格とした新規糖質高分子の分子設計

  松浦和則, 赤坂司, 日比野美紀, 小林一清, 早川芳弘  高分子学会予稿集  48-  (12)  1999
• Synthesis of DNA-Sugar Conjugates and their Characterizations.

  HIBINO MIKI, AKASAKA TSUKASA, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO  高分子学会予稿集  47-  (12)  3130  -3131  1998/09  [Not refereed][Not invited]
  
• Preparation of Plasmid-Sugar Conjugates and their Characterizations.

  AKASAKA TSUKASA, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO, EMI NOBUHIKO  高分子学会予稿集  47-  (11)  2818  -2819  1998/09  [Not refereed][Not invited]
  
• Molecular Recognition of DNA-Sugar Conjugates.

  AKASAKA TSUKASA, HIBINO MIKI, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO  高分子学会予稿集  47-  (4)  756  1998/05  [Not refereed][Not invited]
  
• Synthesis of Sugar-DNA Conjugates by Diazocoupling and their Characterizations.

  HIBINO MIKI, AKASAKA TSUKASA, MATSUURA KAZUNORI, KOBAYASHI KAZUKIYO  高分子学会予稿集  47-  (4)  755  1998/05  [Not refereed][Not invited]
  
• DNAへの糖鎖の導入による構造安定化,ヌクレアーゼ耐性,およびレクチン認識能の賦与

  松浦和則, 赤坂司, 日比野美紀, 小林一清  バイオ・高分子シンポジウム講演要旨集  8th-  1998
• Synthesis of Polymethacrylates having a pendant maltoheptaose moiety by Radical Polymerization and Copolymerization of Methacryloyl maltoheptaoside Derivatives.

  AKASAKA TSUKASA, YOSHIDA TAKASHI, URYU TOSHIYUKI  高分子学会予稿集  46-  (2)  154  1997/05  [Not refereed][Not invited]
  
• Synthesis of Polymethacrylates having a pendant maltoheptaose moiety by Radical Polymerization and Copolymerization of Methacryloyl maltoheptaoside Derivatives.

  赤坂司, 吉田孝, 瓜生敏之  高分子学会予稿集  46-  (2)  1997
• Synthesis of Biological Polymethacrylates Having A Malto-oligosaccharide Chain By Radical Polymerization of Methacryloyl Maltoheptaose Derivative.

  AKASAKA TSUKASA, YOSHIDA TAKASHI, URYU TOSHIYUKI  高分子学会予稿集  45-  (7)  1223  -1224  1996/09  [Not refereed][Not invited]
  

Books etc

• ナノインプリント技術ハンドブック

  応用物理学会・ナノインプリント技術研究会 (Contributor13.6 マイクロ・ナノパターンの歯科バイオ応用)
  オーム社 2019/11 (ISBN: 9784274224485) xiii, 781p
• スタンダード歯科理工学 第７版

  赤坂 司 (Contributor15 接着・合着用材料)
  学建書院 2019/03 (ISBN: 9784762456145)
• スタンダード歯科理工学 第６版

  赤坂 司 (Contributor１４ 接着・合着用材料)
  2016/03
• 動物細胞培養法

  赤坂 司 (Contributor第２章、第３節「カーボンナノチューブ薄膜上での細胞培養」)
  株式会社技術情報協会 2014

Association Memberships

• 代用臓器・再生医学研究会   THE JAPANESE SOCIETY FOR BIOMATERIALS   NANO BIOMEDICAL SOCIETY   日本歯科理工学会   Japanese Society of Carbohydrate Research   

Research Projects

• 天然歯・人工歯の表面へのパターン付与治療へ向けた歯周組織再生の形態ロジック構築

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2024/04 -2027/03 

  Author : 赤坂 司, 横山 敦郎, 吉村 善隆, 宮治 裕史, 牛島 夏未, 星 淡子
• 天然歯・人工歯の表面へのパターン付与治療へ向けた歯周組織再生の形態ロジック構築

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2023/04 -2027/03 

  Author : 赤坂 司, 横山 敦郎, 吉村 善隆, 宮治 裕史, 牛島 夏未, 星 淡子
• マイクロ・ナノパターンの力で誘導・分化させる正常な構造を有する象牙質の再生

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2023/04 -2026/03 

  Author : 吉田 靖弘, 赤坂 司
• 歯の表面に貼り付けて使うセメント質と歯根膜の形状と成分を疑似した人工歯根膜の開発

  日本学術振興会：科学研究費助成事業 挑戦的研究(萌芽)

  Date (from‐to) : 2022/06 -2025/03 

  Author : 赤坂 司
• ２段階薬剤放出性第４世代スキャフォールドの歯周組織再生への応用

  日本学術振興会：科学研究費助成事業 基盤研究(C)

  Date (from‐to) : 2022/04 -2025/03 

  Author : 西田 絵利香, 宮治 裕史, 大矢根 綾子, 中村 真紀, 赤坂 司

   

  アパタイト2層構造化による２段階薬剤放出性第４世代スキャフォールド構築のため，初年度はまず1層目の構築・評価を行った． 1層目として，アパタイトの難溶化（溶解性低下）と抗菌性の期待される生体微量元素（フッ素）を種々の濃度（0～1000 uM）でCaP過飽和溶液に添加し，スキャフォールド上にフッ素含有アパタイト層を作製した． その結果，スキャフォールド内部および外部表面への均一なフッ素含有アパタイト層の生成を確認し，過飽和溶液へのフッ素添加濃度の増加により生成するアパタイト層のフッ素置換率（F/P比で評価）向上が認められた． 成膜後のスキャフォールドを生食に浸漬して溶解性等を評価したところ，過飽和溶液へのフッ素添加濃度の増加に伴い，生食中へのアパタイトの溶解量（7日後）は減少した．アパタイト結晶にフッ化物イオンが取り込まれることにより，層の難溶化したと考えられる，また，生食中へのフッ素溶出量も増加した． 以上より，フッ化物イオンをバイオミメティックコーティング法によりアパタイト層に取り込むことに成功した．フッ化物濃度の増加とともにアパタイト層の溶解度が低下し，減少した．
• Development of micro/nano-patterns to create periodontal ligament sheets with three-dimensionally structures by guiding stem cells

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2020/04 -2023/03 

  Author : Yoshida Yasuhiro

   

  Embryonic stem cells (ES cell) and deciduous dental pulp stem cells (SHED) were focused on as stem cells and their behaviors on various micro/nano-patterns were investigated. Mouse ES cells were cultured on micropatterns and immunostained for differentiation markers in the three germ layers. In most patterns, the order was ectoderm > endoderm > mesoderm, but the proportion of differentiation into endoderm was slightly increased in some of the patterns below 2μm. Cell behaviors on the SHED micropatterns were then investigated. There was no difference in the number of adherent cells in cell adhesion assay, but in cell proliferation and calcification, promotion was observed in specific patterns. These results suggest that the behaviors of stem cells may be controlled by the design of patterns.
• 超立体微細パターン付与だけで歯根膜再生を可能とするインプラント周囲炎治療技術開発

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  Date (from‐to) : 2019/04 -2023/03 

  Author : 赤坂 司, 横山 敦郎, 吉村 善隆, 牛島 夏未, 宮治 裕史, 星 淡子, 加我 公行, 玉井 美保
• Development of intelligent carbon nanomaterials for innovative biomaterials for oral region

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2019/04 -2022/03 

  Author : YOKOYAMA ATSURO

   

  In this study, application of carbon nanomaterials (CNMs) for drug carrier and controlling release of drug, surface modification of Ti with CNMs, and production of CNMs based membrane were done to develop the intelligent carbon nanomaterials (i-CNMs) with high function capable of controlling its expression. Antibiotics was loaded to CNMs. It was able to control the expression of its function by photoirradiation. Also, acceleration of bone formation was observed around Ti by surface modification of Ti with CNMs. CNMs based membrane showed excellent shielding property and maintaining the space for GBR membrane. These results suggested the invention of i-CNMs and its possibility of application for biomaterials.
• 歯科応用へ向けた骨芽細胞機能評価スクリーニング用マイクロ・ナノパターンの開発

  物質・デバイス領域共同研究拠点：2020年度 物質・デバイス領域共同研究拠点

  Date (from‐to) : 2020/03 -2022/03 

  Author : 赤坂 司, 伊東 駿也, 中川 勝, 宮内 昭浩
• 生体応用へ向けた細胞機能評価スクリーニング用マイクロ・ナノパターンの試作

  生体医歯工学共同研究拠点：2019年度 生体医歯工学共同研究拠点共同研究プロジェクト

  Date (from‐to) : 2019/06 -2022/03 

  Author : 赤坂 司, 中川 勝, 伊東 駿也, 宮内 昭浩
• 歯表面で歯医者自身が直接構築できる微細パターンによる歯周病治療法の開発

  文部科学省：科研費 挑戦的研究（萌芽）

  Date (from‐to) : 2018/04 -2021/03 

  Author : 赤坂 司
• Development of smart nano-biomaterials and investigation of possibility on their clinical application for dentistry

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2016/04 -2019/03 

  Author : Yokoyama Atsuro, Bianco Alberto, Takada Sari, Maeda Yukari, Kimura Sadahito

   

  In this study, in order to provide the carbon nanomaterials (CNMs) for clinical application of the dentistry, we observe the biodegradability of carbon nanohorns (CNHs) and modify antibiotics (minocycline) and growth factors (bone morphogenetic proteins) to CNHs. The control of sustained release by LED irradiation of them and their effects were confirmed. Furthermore, we developed titanium with CNHs modified on the surface. We also observed in vivo kinetics of carbon nanotubes (CNTs) locally implanted in mice and suggested that CNTs remain at the site of implantation and do not accumulate in detectable quantities in other organs. These proof-of-concepts will promote future studies on the application of CNMs as smart Nano-Biomaterials which are multifunctionalized for the dentistry.
• マイクロブラシ状コラーゲンからなる人工歯根膜を持つインプラントの開発

  公益財団法人鈴木謙三記念医科学応用研究財団：平成２９年度調査研究助成金

  Date (from‐to) : 2017/12 -2018/11 

  Author : 赤坂 司
• Development of the therapeutic method for peri-implantitis using thin membranes with micro-nano structures

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

  Date (from‐to) : 2014/04 -2017/03 

  Author : Atsuro Yokoyama

   

  In this study, a nano imprint method was used to develop gelatin and titanium sheets with grooved and pillared structures. We investigated the effects of surfaces with micro and nano structures on adhesion and proliferation of osteoblasts, fibroblasts, and epithelial cells. However micro and nano structures accelerated adhesion and proliferation of osteoblasts and fibroblasts, those prevented epithelial cells. These results suggested that the micro and nano grooved and pillared structures effect on adhesion and orientation of osteoblasts, fibroblasts and epithelial cells.
• 歯肉退縮を治療するバイオミメティック次世代歯科治療の開発

  （公）寿原記念財団：研究助成

  Date (from‐to) : 2016/04 -2017/03 

  Author : 赤坂 司
• 三次元構造再生を目指した歯周組織再生用マイクロ・ナノパターン化シートの開発

  文部科学省：科学研究費補助金（基盤研究Ｃ）

  Date (from‐to) : 2013/04 -2017/03 

  Author : 赤坂 司
• Development and evaluation on safety of Hybrid nano biomaterial for reconstruction for oral and maxillofacial region

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2013/04 -2016/03 

  Author : YOKOYAMA ATSURO, AKASAKA Tsukasa, SATO Yoshinori, YAMAMOTO Satoru, TAKITA Hiroko, YUDASAKA Masako, SAKAGUCHI Norihito, SHIBA Kiyotaka

   

  Effects of CNHs on bone formation, surface modification of CNTs and CNHs on titanium and their characteristics on bone formation, and the distribution of CNHs to internal organs used for biomaterial locally were evaluated in this study. CNHs accelerated differentiation of bone marrow cells to osteoblasts by Oncostatin M. The surface modification with CNHs and CNTs increased osteogenesis on titanium. CNHs have not been distributed in other organs on the local delivery.
• 歯肉退縮を止めるための北海道産材料による歯科用マイクロ・ナノパターンシートの開発

  秋山記念生命科学振興財団：研究助成<一般>

  Date (from‐to) : 2014/10 -2015/03 

  Author : 赤坂 司
• 歯肉退縮を防止する歯表面でのマイクロ・ナノパターン直接形成による新規治療法の開発

  科学技術振興機構(JST)：A-STEP 探索タイプ

  Date (from‐to) : 2014/04 -2015/03 

  Author : 赤坂 司
• マイクロ・ナノパターン化バイオマテリアル上での細胞培養

  ナノテクノロジープラットフォーム：平成25年度研究設備の試行的利用

  Date (from‐to) : 2013/04 -2014/03 

  Author : 赤坂 司
• 電気刺激可能なナノ表面構造による細胞機能の制御

  武田科学振興財団：医学系研究奨励

  Date (from‐to) : 2011/04 -2014/03 

  Author : 赤坂 司
• カーボンナノチューブの細胞膜透過特性を利用した抗癌治療の応用開発

  日本学術振興会：科学研究費助成事業 特別研究員奨励費

  Date (from‐to) : 2012 -2013 

  Author : 赤坂 司, 亘理 文夫, CHEN X.

   

  抗癌剤を長間使用すると多剤耐性が発現し、次第に抗癌剤の薬効が減衰する。抗癌剤の作用を保持し癌化学療法の治療効果を上げるには、この多剤耐性を抑制する必要がある。本研究では、代表的なナノマテリアルであるカーボンナノチューブ(CNT)の糖鎖・蛋白質吸着性、細胞膜透過性というユニークな特性に着目し、多剤耐性原因因子の吸着・制御による抗癌治療の高効率化を目的とした。今年度は、2種類のナノカーボン、(1)CNTと(2)ナノダイアモンド(ND)について抗癌薬剤への応用研究を行い、それぞれ新しい進展が得られた。 (1)CNTの多剤耐性抑制効果 : 癌細胞から薬剤を細胞外へ早期に排出させ、抗癌剤の細胞内滞留時間を低減し薬効を減じ、多剤耐性の原因となる因子として細胞膜のポンピング作用を司る蛋白質P-グリコプロテイン(PGP)や多剤耐性関連蛋白質(MRP)がある。CNTを投与すると透過型電子顕微鏡(TEM)観察から細胞内取込が確認され、投与量とともに、m-RNA, PGP総蛋白量、免疫染色のいずれのレベルでもこれらの蛋白量の低下が認められた。これはCNTの抗癌剤の多剤耐性抑制効果のメカニズムの直接的な解明である。 (2)NDのDDS応用のためのステルス性付与 : 現在、開発中のドラッグデリバリーシステム(DDS)においてはターゲット癌組織に至る前に、マクロファージ等の免疫細胞により異物と見なされ捕捉貧食されてれしまうという問題点がある。この問題をいかに回避するかというのは現時点における課題であるが、今回薬剤担体として用いたナノダイアモンドについて表面をポリグリセロール(PG)でコーティングすることにより、異物と認識されず貪食を回避できるステルス性を獲得することが示された。これはDDSの臨床応用にきわめて重要である。
• Development of control technique of iPS cell behavior using CNT-coated electrode for regeneration of tooth

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2010 -2012 

  Author : AKASAKA Tsukasa

   

  For control of functions of iPS cells, chamber with carbon nanotubes (CNTs) electrode was prepared. CNT electrode could maintain undifferentiated state of mouse iPS cells by adjustment of coating and type of CNTs. Patterns of CNT electrode could be printed repeatedly with ink jet printer using CNT inks. The patterns of CNT electrode enabled an arrangement of mouse iPS cells by technique of dielectrophoresis.
• Reconstruction of Jaw Bone with 3 dimension scaffold treated by functionalized carbon nano-material

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2010 -2012 

  Author : YOKOYAMA Atsuro, AKASAKA Tsukasa, YAMAMOTO Satoru, TAKITA Hiroko, SATO Yoshinori, YASUDA Motoaki, SHIBA Kiyotaka, YUDASAKA Masako

   

  Functionalized carbon nanomaterials were developed by covalent bond of b-FGF to multiwalled carbon nanotubes and absorption of simvastatin to carbon nanohorns, and effects of them on bone formation were evaluated by animal experiments. Extensive bone formation was observed in the scaffolds with functionalized carbon nanomaterials in comparison with normal carbon nanomaterials. Also, biocompatibility carbon nanomaterials was observed by animal experiments for a long term.
• 微粒子・ナノ材料を応用した石灰化誘導能を有する自己修復材料の開発

  文部科学省：科学研究費補助金(基盤研究(C))

  Date (from‐to) : 2010 -2012 

  Author : 加我 正行, 橋本 正則, 赤坂 司

   

  機能性ガラスであるS-PRG緻粒子を添加したシーラント材と充填材料(グラアイオノマーセメントとレジン)から溶出するアルカリ性イオンの種類と溶出量を測定し、それらの酸緩衝能を調べた。硬化した試料を乳酸溶液に浸漬するとイオン溶出効果が発現した。歯質がう蝕になる環境は、う蝕原因菌の酸産生によりpHが5.5以下になるとハイドロキシアパタイトが分解される。ここでアルカリ性イオンを放出する材料により脱灰が抑制され、再石灰誘導が生じる。この作用は材料は本研究で使用したバイオグラス、MTA等にもみられた。これら材料の配合比率を検索しながら再石灰化誘導の実験を行った。象牙質切片と微粒子を添加した実験材料との間に10μmのスペースを作り両端を固定して、人工唾液と蒸留水中に37℃で長期間保存し、象牙質切片表面上の析出物、結晶成分のSEM観察とエックス線回折とレーザーラマン分光光度計による同定を行った。試料から溶出するアルカリ性イオンや抗菌性のイオン、燐酸アパタイトの構成成分のカルシウムが再石灰化誘導に関与してる様子がわかり、人口唾液に浸漬した場合に析出物が6ヶ月目でわずかに観察された。SEM観察によりフラットな円盤状象牙質表面に針状の結晶が観察された。EDXによる析出物の同定から主に燐酸カルシウムと判断できた。長期的な展望に立った研究が必要である。実験試料とヒト抜去歯の接着強度の測定を微小引張試験(マイクロテンサイル)方法で行った。S-PRGを含有したレジンは歯質との接着方法の工夫により安定した接着強度が得られた。
• Development of nanofiber reinforced resin using various nanotubes

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2009 -2011 

  Author : UO Motohiro, AKASAKA Tsukasa, ABE Shigeaki

   

  Carbon nanotubes(CNTs) are fibrous crystalline material which have several to several ten nanometers in diameter. CNTs shows high mechanical strength close to the theoretical value, then the application as the structural material. In this study, preparation of the monolith and composite of CNTs and their application for dental and medical materials were studied. CNTs were successfully sintered using the spark plasma sintering and CNTs monolith showed similar elastic modulus to bone. CNTs/collagen composite films were also prepared. The film shows good tensile strength and flexibility.
• iPS細胞の未分化培養に有効な北海道産材料を用いた培養基材の探索

  ノーステック財団：研究開発助成事業 （タレント補助金）

  Date (from‐to) : 2009/10 -2010/03 

  Author : 赤坂 司
• シリコーンゴム剤における細胞培養機能の評価

  全国中小企業団体中央会：ものづくり中小企業製品開発等支援補助金

  Date (from‐to) : 2009/04 -2010/03 

  Author : 赤坂 司
• カーボンナノチューブ透明導電性薄膜での近赤外照射による殺菌

  ノーステック財団：研究開発助成事業 （タレント補助金）

  Date (from‐to) : 2008/10 -2009/03 

  Author : 赤坂 司
• カーボンナノチューブコート細胞培養用ディッシュの新たな機能探索

  北海道大学：総長室重点配分経費 （若手研究者自立支援）

  Date (from‐to) : 2008/07 -2009/03 

  Author : 赤坂 司
• 単層CNTを利用した新規細胞培養方法の開発

  科学技術振興機構(JST)：産学共同シーズイノベーション化事業（顕在化ステージ）

  Date (from‐to) : 2008/04 -2009/03 

  Author : 赤坂 司
• Oral Tissue Reconstruction with 3D Scaffolds and Surface Modification Using Carbon Nanotubes

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2007 -2009 

  Author : Atsuro YOKOYAMA, Tsukasa AKASAKA, Yoshinori SATO, Satoru YAMAMOTO, Motoaki YASUDA, Masanobu SHINDO, Fumihiro HIGASHINO

   

  In this study, we developed 3D collagen scaffolds coated with carbon nanotubes to reconstruct jaw bone. It was shown that initial adhesion and spreading of osteoblastic cells on 3D collagen scaffold was accelerated by CNTs coating, especially center part of scaffold. Also, it was suggested to apply CNTs for reconstruction of jaw bone, because excellent osteoconductivy was observed when 3D collagen scaffolds coated with CNTs were implanted in bone.
• Chemical state analysis of rarely contained biological metallic element using X-ray absorption fine structure (XAFS) analysis

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2006 -2009 

  Author : Motohiro UO, Kiyotaka ASAKURA, Fumio WATARI, Atsuro YOKOYAMA, Tsukasa AKASAKA, Shigeaki ABE

   

  In this study, the chemical state of metallic elements and micro foreign bodies contained in the biological tissues were analyzed using XAFS method and the behavior of dental and medical alloys (e.g.titanium, nickel-titanium alloy, chromium-based alloy) was evaluated. Titanium in the surrounding tissues of dental and medical implants was usually existed as the metallic Ti, but, the titanium oxide was also detected. The titanium oxide was considered as derived from the dissolved and precipitated Ti. Nickel was existed as the ionic state in the surroundings of nickel-based alloy, then, the toxic effect of Ni ion to the surrounding tissues was concerned. In addition, trace element in the tussues (e.g.Se) analysis and micro XAFS analysis were also carried. In conclusion, the possibility of XAFS analysis for the biological tissue was suggested.
• カーボンナノチューブによるミュータンス菌の除菌および殺菌効果

  ノーステック財団：基盤的研究開発育成事業補助金 （若手研究補助金）

  Date (from‐to) : 2007/10 -2008/03 

  Author : 赤坂 司
• 人工複合糖質高分子およびレクチンを用いた口腔内細菌が認識する糖鎖構造の解明

  秋山記念生命科学振興財団：研究助成 （奨励助成）

  Date (from‐to) : 2006/08 -2007/03 

  Author : 赤坂 司
• カーボンナノチューブ(CNTs)の生物学的特性を応用した再生療法の開発

  文部科学省：科学研究費補助金(萌芽研究)

  Date (from‐to) : 2005 -2006 

  Author : 横山 敦郎, 赤坂 司, 進藤 正信, 山本 悟

   

  本年度においては、多層カーボンナノチューブ(MWCNTs)を吸着することにより作製したスキャホールド上で骨髄細胞をデキサメサゾン(Dex)で骨芽細胞に誘導し、遺伝子発現に及ぼすMWCNTsの影響を検索するとともに、Dex添加と非添加の条件で骨髄細胞を培養したスキャホールドを、細胞を付着させた状態でラットの皮下組織に埋入した。 ラット骨髄細胞のDex誘導後1、3および7日の遺伝子の発現を、MWCNTsを吸着したスキャホールドで培養した場合とポリスチレンディッシュ上で培養した場合について、マイクロアレイを用いて比較検討した。全期間を通してMWCNTs固着スキャホールドで、インターロイキンなどの炎症に関与する遺伝子の発現が強く認められ、1、3日では、Matrix Gra ProteinやInsulin like Growth Factorなどの骨に関連する遺伝子の発現が、また7日ではインテグリンなどの接着に関与する遺伝子の発現が強く認められた。この結果から、MWCNTsは起炎性を有するが、骨髄細胞をより速く骨芽細胞に分化・誘導する可能性が示唆された。骨髄細胞をMWCNTs上でDexを添加して2週間培養した後、ラット皮下組織に6週間埋入すると、骨組織様の構造が認められたが、Dexを添加せずに培養した場合は観察されなかった。これらのことから、Dexを添加しMWCNTs上で骨髄細胞を培養すると骨芽細胞に分化し、皮下組織内で骨組織を形成する可能性が示唆された。 以上の結果から、MWCNTsをスキャホールドに用いると、骨髄細胞を強固にスキャホールドに付着した状態で骨芽細胞への分化を促進し、さらにこのスキャホールドは軟組織内で骨組織を形成する可能性が示された。
• 歯科用糖鎖ナノ材料の調製および歯周病細菌との相互作用

  文部科学省：科学研究費補助金(若手研究(B))

  Date (from‐to) : 2004 -2006 

  Author : 赤坂 司

   

  歯周病の原因である歯周病細菌の歯への定着を阻害する歯科用糖鎖ナノ材料の開発を目的とし、カーボンナノチューブやその糖鎖修飾体とし、効率的に歯周病細菌へ結合する歯科用ナノ糖鎖材料を開発する。 糖鎖自体の効果をより明白とするため、ポリスチレンディッシュに様々な糖鎖構造を持つ人工複合糖質高分子を吸着させ、基盤表面へのStreptococcus mutans(S.mutans)の吸着を検討した。その結果、ラクトースやキトビオース構造に対して付着し、さらにキトビオース構造は、S.mutansの増殖を抑制することが明らかとなった。 カーボンナノチューブによる口腔内細菌の捕捉を効率化するため、カーボンナノチューブの二次的な形態(直鎖状および球状)による菌体吸着の影響を検討した結果、両方の形態にて細菌捕捉が効率的に起こるものの、直鎖状のカーボンナノチューブの方がより効率的に菌体を吸着することが分かった。また、カーボンナノチューブにより吸着された細菌は引き続き培養を行うと細菌は増殖する事より、カーボンナノチューブによる相互作用自体は殺菌的ではなく吸着による除菌的効果であることが分かった。 以上の結果より、付着能や増殖抑制能を持つ糖鎖により修飾された直鎖状のカーボンナノチューブ網による細菌の捕捉が効率的であると考えられる。今後、カーボンナノチューブ自体に条件付与にて殺菌能の発現などの更なる効率化・機能付与化が望まれる。
• Development of regenerative therapy for jaw bone using scaffold with carbon nanotubes.

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2004 -2006 

  Author : Atsuro YOKOYAMA, 安田 元昭, 赤坂 司, 進藤 正信, 堀内 留美

   

  In this study, investigation of biocompatibility of carbon nanotubes (CNTs), cell culture on the scaffold using with CNTs and fabrication of bulk CNTs were carried out for the purpose of reconstruction of jaw bone using with CNTs. CNTs were implanted in the subcutaneous tissue in rats for 2 years, and histological and ultramicrostructural investigation to CNTs were done. Some CNTs were observed in lysosome in macrophages and only slight granulomatous inflammatory response was recognized around CNTs at 2 years, although granulation tissue with phagocytes was seen around CNTs at early stage after implant. The degree of aggregation of CNTs became to slight with time. Most of typical structure of CNTs like tubes was not changed after 2 years by observation using TEM. These results suggested that CNTs was not strong prophlogistic substance and structure of crystal of CNTs was stable in vivo. Scaffolds with CNTs were made by vacuum filtration of the dispersed CNTs slurry onto polycarbonate (PC) membrane. Saos-2 (human osteoblast-like cell) was cultured on the scaffolds. Proliferation and alkaline phosphatase activity of Saos-2 cultured on the CNTs scaffolds were higher than those of PC membrane. Application of the CNTs scaffold for guided bone regeneration membrane to bone defects made on rat parietal bone was effective in osteogenesis compared to PC membrane. Bulk CNTs materials were fabricated by spark plasma sintering (SPS). Physical and mechanical properties of bulk CNTs were close to those of bone, and biocompatibility was excellent. These results showed that bulk CNTs made by SPS method was suitable for bone substitute materials. From these results, it was suggested that regenerative therapy for jaw bone using with CNTs would be possible.
• Biological applications of carbon nanotubes

  Funded Research

  Date (from‐to) : 2002 -2004
• Effect of particle size on biocompatibility and biochemical evaluation of properties for various materials

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2002 -2003 

  Author : Fumio WATARI, 高師 則行, 戸塚 靖則, 宇尾 基弘, 横山 敦郎, 赤坂 司

   

  [Purpose]In dental material the powder/liquid method is abundantly used and abrasion powder arises in the sliding part of artificial joint. To study the effect of powders on health the size dependence of fine particles on biocompatibility was investigated by cell functional test and implantation test. [Method] Monodispersed particles were extracted by sedimentation for the size 0.5, 3, 10μm and by ultrafiltration for less than 300nm. The particles were thus prepared with the same size for different materials. [Size dependence] In cell functional test using the human neutrophil, periodontal ligament cell and rat macrophage, the cell survival rate was lowered and the emission of LDH, oxygen radical, cytokines TNF-α, IL-1β, IL-8, M-CSF increased as particle size became smaller, for Ti, Fe, Ni(each 500nm ; 3,10, 50, 150μm), TiO_2(30, 60, 300, 500nm ; 2μm), polylactic acid (1, 13μm). Especially, for the case of smaller than 10μm where phagocytosis was induced, the effect was remarkably pronounced. The stimulatibility of these effects is lower by about 1/100〜1/1000 than the intracellular toxicity. [Material dependence]Both Ti whose ionic dissolution was negligible, confirmed by the ICP elemental analysis, and Fe, much more dissolvable, showed the similar size dependency. In Ni, cell survival rate was lower, emission of oxygen radical and cytokine was larger, the cell destruction was observed by microscopy, which was due to the stronger cytotoxicity of Ni. [Conclusion]In animal implantation test, Ti particles showed biocompatibility for the size larger than about 100μm, and inflammation for smaller than 50μm. For less than 10μm phagocytosis was induced and inflammation was continued for the long term. For the biocompatibility in the material with a macroscopic size the material-dependent, chemical effect through dissolved ions is generally dominant. For the range of μm〜nm, the material-independent, physical size effect origined from the relative size relation between particles and cell/tissue becomes tangible, even for the bioactive and bioinert materials.

Industrial Property Rights

• 特開2009-142218:細胞培養容器およびその製造方法  2009/07/02

  橋本 剛, 赤坂 司, 横山 敦郎, 亘理 文夫  株式会社名城ナノカーボン, 国立大学法人 北海道大学  200903090569528237
• 特開2009-016326:透明導電性薄膜およびその製造方法  2009/01/22

  橋本 剛, 赤坂 司, 横山 敦郎, 亘理 文夫  株式会社名城ナノカーボン  200903019440058521
• 特開2000-086693:DNA糖鎖コンジュゲートおよびその製造方法  2000/03/28

  小林 一清, 松浦 和則, 赤坂 司, 日比野 美紀  ヘキスト リサーチ アンド テクノロジー株式会社  200903053590484247
• DNA糖鎖コンジュゲートおよびその製造方法

  特許公開2000-086693
• 細胞培養容器およびその製造方法

  特許出願2007-323658
• 透明導電性薄膜およびその製造方法

  特許出願2007-202344