MF研究者総覧

研究者データベース

詳細
居城　邦治(イジロ　クニハル)
電子科学研究所　生命科学研究部門
教授
researchmap個人ページ
Last Updated :2024/05/09

基本情報

所属

  • 電子科学研究所　生命科学研究部門

職名

  • 教授

学位

  • 工学博士（東京工業大学）

ホームページURL

J-Global ID

研究キーワード

  • 超分子化学   

研究分野

  • ナノテク・材料 / ナノ構造化学

担当教育組織

職歴

  • 2021年04月 - 現在 北海道大学 電子科学研究所 所長
  • 2007年11月 - 現在 理化学研究所 客員主幹研究員
  • 2004年03月 - 現在 北海道大学 電子科学研究所 教授
  • 1998年04月 - 2004年03月 北海道大学 電子科学研究所 助教授
  • 2000年12月 - 2003年09月 科学技術振興事業団 さきがけ研究２１（「変換と制御」領域） 研究員
  • 1999年07月 - 1999年10月 文部科学省在外研究員 Max Planck Institut für Polymerforschung
  • 1994年12月 - 1999年10月 科学技術振興事業団 さきがけ研究２１（「場と反応」領域） 研究員
  • 1994年04月 - 1998年03月 北海道大学 電子科学研究所 講師
  • 1993年01月 - 1994年03月 フンボルト財団 Johannes Gutenberg-Universität Mainz 客員研究員
  • 1992年04月 - 1994年03月 東京工業大学 生命理工学部 助手
  • 1991年04月 - 1992年03月 日本学術振興会 特別研究員（PD）
  • 1990年04月 - 1991年03月 日本学術振興会 特別研究員（DC）

学歴

  • 1988年04月 - 1991年03月   東京工業大学   大学院理工学研究科   博士課程
  • 1986年04月 - 1988年03月   東京工業大学   大学院理工学研究科   修士課程
  • 1982年04月 - 1986年03月   東京工業大学   工学部

所属学協会

  • American Association for the Advancement of Science   American Chemical Society   高分子学会 バイオ・高分子研究会   高分子学会   電気化学会   応用物理学会   日本化学会   

研究活動情報

論文

  • Yoshiki Suganami, Tomoya Oshikiri, Hideyuki Mitomo, Keiji Sasaki, Yen En Liu, Xu Shi, Yasutaka Matsuo, Kuniharu Ijiro, Hiroaki Misawa
    ACS Nano 18 6 4993 - 5002 2024年02月13日 
    We developed a substrate that enables highly sensitive and spatially uniform surface-enhanced Raman scattering (SERS). This substrate comprises densely packed gold nanoparticles (d-AuNPs)/titanium dioxide/Au film (d-ATA). The d-ATA substrate demonstrates modal ultrastrong coupling between localized surface plasmon resonances (LSPRs) of AuNPs and Fabry-Pérot nanocavities. d-ATA exhibits a significant enhancement of the near-field intensity, resulting in a 78-fold increase in the SERS signal for crystal violet (CV) compared to that of d-AuNP/TiO2 substrates. Importantly, high sensitivity and a spatially uniform signal intensity can be obtained without precise control of the shape and arrangement of the nanoscale AuNPs, enabling quantitative SERS measurements. Additionally, SERS measurements of rhodamine 6G (R6G) on this substrate under ultralow adsorption conditions (0.6 R6G molecules/AuNP) show a spatial variation in the signal intensity within 3%. These findings suggest that the SERS signal under modal ultrastrong coupling originates from multiple plasmonic particles with quantum coherence.
  • Yu Sekizawa, Yuka Hasegawa, Hideyuki Mitomo, Chisato Toyokawa, Yusuke Yonamine, Kuniharu Ijiro
    Advanced Materials Interfaces 2024年01月10日 
    Abstract Gold nanorods (AuNRs) have unique optical properties such as transverse and longitudinal localized surface plasmon resonance (T‐ and L‐LSPR). As the L‐LSPR absorption depends on the angle of the AuNRs to incident light and polarization, orientational control of AuNRs is a crucial issue. In spite of various techniques to control AuNR orientation, dynamic orientation tuning on a solid substrate remains challenging. Herein, dynamic changes are demonstrated in AuNR orientation in the anionic polymer (DNA) brushes via control of their thickness by salt concentration. AuNRs vertically align toward the substrates when their thickness exceeds the AuNR length. Once their thickness becomes shorter than the AuNR length, the attached AuNRs begin to tilt. The tilt reaches a maximum level close to horizontal when the thickness decreases to half that of the AuNR length. The dynamic control between the vertical (uniform) and tilted (random) orientation of the AuNRs showed not only absorption intensity changes in L‐LSPR but also the switching of side‐by‐side plasmon coupling. The polymer brush‐based system affords a novel platform for the stimuli‐responsive control of AuNR orientation on the substrates via changes in the thickness of polymer brushes for actively tunable plasmonic substrates.
  • Jinjian Wei, Yi Yu, Yasutaka Matsuo, Liang Zhang, Hideyuki Mitomo, Yuqin Chen, Kuniharu Ijiro, Zhide Zhang
    Langmuir 39 49 17939 - 17946 2023年12月01日
  • ヒメマスの椎骨における骨強度と骨質の椎骨位置依存性
    河本 千宙, 中居 豪佑, 堀内 秀与, 中村 郁哉, 弘中 翔大, 三友 秀之, 居城 邦治, 佐々木 直樹, 木村 廣美[須田]
    日本骨形態計測学会雑誌 33 1 176 - 176 日本骨形態計測学会 2023年05月
  • Li Kong, Luyang Wang, Yali Shi, Lin Peng, Xingguo Liang, Guoqing Wang, Hideyuki Mitomo, Tohru Takarada, Kuniharu Ijiro, Mizuo Maeda
    ACS Applied Nano Materials 5 8 10321 - 10330 2022年08月26日
  • ベニザケ椎骨におけるミネラル代謝の可視化解析
    河本 千宙, 堀内 秀与, 中村 郁哉, 弘中 翔大, 三友 秀之, 居城 邦治, 木村 廣美[須田]
    日本骨代謝学会学術集会プログラム抄録集 40回 134 - 134 (一社)日本骨代謝学会 2022年07月
  • Miki Nakano, Osamu Miyashita, Yasumasa Joti, Akihiro Suzuki, Hideyuki Mitomo, Yoshiya Niida, Ying Yang, Hirokatsu Yumoto, Takahisa Koyama, Kensuke Tono, Haruhiko Ohashi, Makina Yabashi, Tetsuya Ishikawa, YOSHITAKA BESSHO, Kuniharu Ijiro, Yoshinori Nishino, Florence Tama
    Optica 2022年06月06日
  • ヒメマスとベニザケ幼魚,親魚の生息環境が各骨質,骨強度に及ぼす影響
    河本 千宙, 堀内 秀与, 中村 郁哉, 弘中 翔大, 三友 秀之, 居城 邦治, 木村 廣美[須田]
    日本骨形態計測学会雑誌 32 1 S191 - S191 日本骨形態計測学会 2022年05月
  • Hideyuki Mitomo, Chie Takeuchi, Ryo Sugiyama, Kaoru Tamada, Kuniharu Ijiro
    Bulletin of the Chemical Society of Japan 95 5 771 - 773 2022年05月 
    Cube-structured silver nanoparticles (AgNCs) were synthesized and modified with oligo(ethylene glycol) (OEG)-attached alkane-thiol ligands. They showed thermo-responsive color changes dispersed in water and also good dispersibility in CHCl3. They formed well-packed assembled structures at the airwater interface. AgNC assembled films also showed a strong plasmonic property and thermo-responsiveness.
  • Joshua Chidiebere Mba, Hideyuki Mitomo, Yusuke Yonamine, Guoqing Wang, Yasutaka Matsuo, Kuniharu Ijiro
    NANOMATERIALS 12 9 2022年05月 
    Anisotropic gold nanodiscs (AuNDs) possess unique properties, such as large flat surfaces and dipolar plasmon modes, which are ideal constituents for the fabrication of plasmonic assemblies for novel and emergent functions. In this report, we present the thermo-responsive assembly and thermo-dynamic behavior of AuNDs functionalized with methyl-hexa(ethylene glycol) undecane-thiol as a thermo-responsive ligand. Upon heating, the temperature stimulus caused a blue shift of the plasmon peak to form a face-to-face assembly of AuNDs due to the strong hydrophobic and van der Waals interactions between their large flat surfaces. Importantly, AuNDs allowed for the incorporation of the carboxylic acid-terminated ligand while maintaining their thermo-responsive assembly ability. With regard to their reversible assembly/disassembly behavior in the thermal cycling process, significant rate-independent hysteresis, which is related to their thermo-dynamics, was observed and was shown to be dependent on the carboxylic acid content of the surface ligands. As AuNDs have not only unique plasmonic properties but also high potential for attachment due to the fact of their flat surfaces, this study paves the way for the exploitation of AuNDs in the development of novel functional materials with a wide range of applications.
  • Han Lin, Hideyuki Mitomo, Yusuke Yonamine, Zhiyong Guo, Kuniharu Ijiro
    CHEMISTRY OF MATERIALS 34 9 4062 - 4072 2022年05月 
    The emerging concept of tunable plasmonicchirality is mostly observed as a reconfigurable behavior or afeature of complex chiral plasmonic assemblies. For discretecolloidal particles, it is challenging to achieve reversible tunabilityor a transient response with regard to chiroptical activities,particularly in the visible or near-infrared region. Herein, wedemonstrate a stimulus-responsive system based on chiralmolecule-achiral plasmonic nanoparticles coated with polyaniline(PANI) as a variable dielectric layer, in whichL-/D-cysteinemolecules are introduced between the gold core and the shell as astatic chiral source, allowing the chiral transfer effect to be greatlyamplified by the hotspot gap of sub-monomolecular thickness. By taking advantage of the responsive properties to either pH or theelectric potential dual stimuli of PANI, which also provides a stable and real-time switchable dielectric environment for the wholesystem, dynamic tuning of the plasmon and its induced chiroptical activities of core-gap-shell nanoparticles@PANI were preciselyobtained. This well-defined design provides an open platform forflexible and rational tailoring of plasmonic cores, chiral molecules,and variable dielectrics to chiroptical needs, which is important for realizing applications in chemical sensing, chiral nanocatalysis,enantioselective separations, and novel optical devices
  • Satoshi Nakamura, Hideyuki Mitomo, Shigeaki Suzuki, Yu Torii, Yu Sekizawa, Yusuke Yonamine, Kuniharu Ijiro
    CHEMISTRY LETTERS 51 5 529 - 532 2022年05月 
    Assemblies of cationic gold nanorods (AuNRs) via electrostatic interactions with double-stranded (ds) DNA were investigated in solution and after evaporation as a cast-film. Interestingly, moderately positively charged AuNRs assembled with dsDNA provided a monolayer sheet with an ordered alignment resembling a two-dimensional (2D) smectic structure during solvent evaporation.
  • Kosuke Nagata, Ken-Ichi Bajo, Hideyuki Mitomo, Ryosuke Fujita, Ryota Uehara, Kuniharu Ijiro, Hisayoshi Yurimoto
    Cell structure and function 46 2 95 - 101 2021年09月25日 
    Among the inheritance of cellular components during cell division, deoxyribonucleic acid (DNA) and its condensate (chromosome) are conventionally visualized using chemical tag-labeled nucleotide analogs. However, associated mutagenesis with nucleotide analogs in the visualization of chromosomes is cause for concern. This study investigated the efficiency of using stable isotope labels in visualizing the replicating cultured human cell-chromosomes, in the absence of analog labels, at a high spatial resolution of 100 nm. The distinct carbon isotope ratio between sister chromatids reflected the semi-conservative replication of individual DNA strands through cell cycles and suggested the renewal of histone molecules in daughter chromosomes. Thus, this study provides a new, powerful approach to trace and visualize cellular components with stable-isotope labeling.Key Words: stable isotope, chromosome replication, semi-conservative replication, imaging, mass spectrometry.
  • Jinjian Wei, Xiaoying Huang, Liang Zhang, Yuqin Chen, Kenichi Niikura, Hideyuki Mitomo, Kuniharu Ijiro, Zhide Zhang
    Langmuir 37 32 9694 - 9700 2021年08月17日 [査読有り]
     
    Water-stable gold nanoparticle vesicles (GNVs) with hollow interiors have attracted attention due to their great potential for biological applications; however, their preparation through the self-assembly approaches has been restricted due to the limited understanding of their critical mechanistic issues. In this paper, we demonstrate that a fluorinated tetra (ethylene glycol) (FTEG)-terminated tetra (ethylene glycol) (EG4), namely, FTEG-EG4, ligand can self-assemble with gold nanoparticles (5 and 10 nm) into GNVs with a hollow structure in THE due to the solvophobic feature of the ligand. Time-dependent studies showed that the GNVs with a closely packed surface derived from the incomplete and irregular GNVs, but not through the fusion of the GNV precursors. After dialysis in water, the assemblies retained vesicular structures in water, even though GNVs aggregated together, which was initiated by the hydrophobic interactions between the FTEG heads of the surface ligands on GNVs. This study provides a new insight into the design of novel small surface ligands to produce water-stable GNVs for biological applications.
  • ヒメマスおよびベニザケ椎骨の骨評価
    堀内 秀与, 弘中 翔大, 中村 郁哉, 河本 千宙, 松尾 保孝, 三友 秀之, 居城 邦治, 木村 廣美[須田]
    日本骨形態計測学会雑誌 31 2 S130 - S130 日本骨形態計測学会 2021年06月
  • Kun Xiong, Hideyuki Mitomo, Xueming Su, Yier Shi, Yusuke Yonamine, Shin-ichiro Sato, Kuniharu Ijiro
    Nanoscale Advances 3 13 3762 - 3769 2021年03月26日 [査読有り]
     

    Thermo-responsive properties of oligo(ethylene glycol) derivatives attached on gold nanoparticles were tuned via local environmental control not only by the hydrophobic moiety at their terminus but also by their molecular configuration.

  • Yali Shi, Qian Li, Yao Zhang, Guoqing Wang, Yasutaka Matsuo, Xingguo Liang, Tohru Takarada, Kuniharu Ijiro, Mizuo Maeda
    JOURNAL OF MATERIALS CHEMISTRY C 8 45 16073 - 16082 2020年12月 
    Hierarchical plasmonic nanostructures that embed multiple shape-discrete domains and thereby unique plasmon resonance have implications in detection, diagnostics, and photovoltaics. Despite great progress in self-assembly of gold nanostructures, direct synthesis of hierarchical Au nanostructures that afford dense and steady intrinsic hotspots has remained less explored. This is partially because nanocrystal growth principally yields symmetrical nanocrystals with simple morphologies in monometallic systems. We report on the seeded synthesis of "Au nanograsses" on Au nanoplates that comprise an array of bent Au nanowire and exhibit total light absorption and intrinsically coupled plasmon resonance. The growth of Au nanograsses is achieved through competition between Au deposition and surface ligand passivation, which restricts the deposition of upcoming Au atoms onto the freshly deposited Au surfaces that have not been passivated. By controlling reaction kinetics and ligand passivation, the secondary nanostructures can be tuned from nanowires to nanotubes and near-spherical islands. Theoretical simulations indicate a stronger near-field electromagnetic field and a denser distribution of built-in hotspots of the Au nanograss than the near-spherical nanoisland array. Application of the Au nanograss in single-particle surface-enhanced Raman scattering (SERS) reveals a greatly elevated enhancement effect of the Au nanograss compared to the nanoisland array by nearly one order-of-magnitude.
  • Takashi Kimura, Akihiro Suzuki, Ying Yang, Yoshiya Niida, Akiko Nishioka, Masashi Takei, Jinjian Wei, Hideyuki Mitomo, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro, Kensuke Tono, Makina Yabashi, Tetsuya Ishikawa, Tairo Oshima, Yoshitaka Bessho, Yasumasa Joti, Yoshinori Nishino
    Review of Scientific Instruments 91 8 083706 - 083706 2020年08月01日 [査読有り][通常論文]
  • Satoshi Nakamura, Hideyuki Mitomo, Yusuke Yonamine, Kuniharu Ijiro
    Chemistry Letters 49 7 749 - 752 2020年07月05日 [査読有り]
     
    In this study, we demonstrate that the plasmonic properties of gold nanorods (GNRs) electrostatically adsorbed on a DNA brush substrate are reversibly controlled by changes in NaCl concentration. This plasmonic change results from GNR assembly/disassembly in a DNA brush layer. In addition, we show that this active plasmonic system exhibits intense and switchable chiroptical properties.
  • Ken-Ichi Sano, Tsubasa Yuki, Yuta Nomata, Norihisa Nakayama, Ryo Iida, Hideyuki Mitomo, Kuniharu Ijiro, Yoshihito Osada
    Biochemistry 59 23 2194 - 2202 2020年06月16日 [査読有り]
     
    Tropomyosin (Tpm) is a two-stranded parallel alpha-helical coiled-coil protein, and studying its structure is crucial for understanding the nature of coiled coils. Previously, we found that the N-terminal half of the human skeletal muscle alpha-Tpm (alpha-Tpm 140) was less structurally stable in the presence of phosphate ions than the coiled-coil protein carrier (CCPC) 140 variant with 18 mutated residues, in which all amino acid residues located at the interface between the two alpha-helices were completely conserved. A classical hypothesis explains that interhelical interactions stabilize the coiled-coil structure. In this study, we tested the hypothesis that the structural stability of Tpm and its variant is governed by the binding of multivalent ions that form a bridge between charged side chains located at positions b, c, and f of the heptad repeat on a single alpha-helical chain. We found that the structural stability of alpha-Tpm 140 and CCPC 140 markedly increased upon addition of divalent cations and divalent anions, respectively. We also clarified that the structural stability of the alpha-Tpm 140/CCPC 140 heteromeric coiled-coil molecule was governed by the stability of a less stable alpha-helical chain. These results demonstrated that the entire structural stability of Tpm is determined by the stability of a single alpha-helix. Our findings provide new insights into the study of the structure of coiled-coil proteins.
  • Yu Sekizawa, Hideyuki Mitomo, Mizuki Nihei, Satoshi Nakamura, Yusuke Yonamine, Akinori Kuzuya, Takehiko Wada, Kuniharu Ijiro
    Nanoscale Advances 2 9 3798 - 3803 2020年05月22日 [査読有り]
     

    Gold nanorod (GNR) arrays were prepared by GNR attachment on anionic polymer brushesviaelectrostatic interactions and their orientation reversibly changed by the modulation of interactions between GNRs and polymersviachanges in the solution pH.

  • ステロイド性骨粗鬆症モデルラットにおける骨強度と骨密度および骨質の関係
    中村 郁哉, 佐藤 大, 藤田 諒, 長谷川 智香, 堀内 秀与, 桝谷 朋美, 太田 昌博, 高畑 雅彦, 居城 邦治, 網塚 憲生, 木村 廣美[須田]
    日本骨形態計測学会雑誌 30 1 S134 - S134 日本骨形態計測学会 2020年05月
  • Satoshi Nakamura, Hideyuki Mitomo, Yu Sekizawa, Takeshi Higuchi, Yasutaka Matsuo, Hiroshi Jinnai, Kuniharu Ijiro
    Langmuir 36 13 3590 - 3599 2020年04月07日 [査読有り]
     
    The development of a strategy for the assembly of nanoscale building blocks, in particular, anisotropic nanoparticles, into desired structures is important for the construction of functional materials and devices. However, control over the orientation of rodshaped nanoparticles on a substrate for integration into solid-state devices remains challenging. Here, we report a strategy for the fabrication of finely aligned gold nanorod (GNR) arrays using polymer (DNA) brushes as a nanoscale template. The gold nanorods modified with cationic surface ligands were electrostatically adsorbed onto the DNA brush substrates under various conditions. The orientational behavior of the GNRs was examined by spectral analyses and transmission electron microtomography (TEMT). As a result, we found several important factors, such as moderate interaction between GNRs and polymers and polymer densities on the substrate, related to the vertical alignment of GNRs on the substrates. We also developed a purification method to remove the undesired adsorption of GNRs onto the arrays. Finally, we have succeeded in the fabrication of extensive vertical GNR arrays of high quality via the easy bottom-up process.
  • Satoshi Nakamura, Hideyuki Mitomo, Miho Aizawa, Takeharu Tani, Yasutaka Matsuo, Kenichi Niikura, Andrew Pike, Masayuki Naya, Atsushi Shishido, Kuniharu Ijiro
    ACS omega 4 15 16701 - 16701 2019年10月08日 [査読有り][通常論文]
     
    [This corrects the article DOI: 10.1021/acsomega.7b00303.].
  • Satoru Hamajima, Hideyuki Mitomo, Takeharu Tani, Yasutaka Matsuo, Kenichi Niikura, Masayuki Naya, Kuniharu Ijiro
    Nanoscale Advances 1 5 1731 - 1739 2019年03月 [査読有り]
     

    Nanoscale imaging and spectral analyses support the tremendous potential of the active tuning of nanostructures by hydrogels.

  • Colette J. Whitfield, Rachel C. Little, Kasid Khan, Kuniharu Ijiro, Bernard A. Connolly, Eimer M. Tuite, Andrew R. Pike
    Chemistry – A European Journal 24 57 15267 - 15274 2018年10月12日 [査読有り]
  • Jinjian Wei, Hideyuki Mitomo, Takeharu Tani, Yasutaka Matsuo, Kenichi Niikura, Masayuki Naya, Kuniharu Ijiro
    Langmuir 34 41 12445 - 12451 2018年09月 [査読有り][通常論文]
     
    The self-assembly of gold nanoparticles (GNPs) into a defined structure, particularly hollow capsule structures, provides great potential for applications in materials science and medicine. However, the complexity of the parameters for the preparation of those structures through self-assembly has limited access to critical mechanistic questions. With this in mind, we have studied GNP vesicle (GNV) formation through self-assembly by the surface modification of GNPs with low-molecular-weight ligands. Here, we successfully prepared GNVs composed of GNPs with a diameter of 30 nm by surface modification with carboxylic acid-terminated fluorinated oligo(ethylene glycol) ligands (CFLs). As the carboxylic acid has two states (protonated and deprotonated), the balance of the attraction and repulsion between GNPs covered with CFLs is tunable. Sodium carboxylate-terminated fluorinated oligo(ethylene glycol) ligands (SCFLs) provided smaller GNVs than did CFLs at 0.8 X 10(11) NPs/mL. Time-course study revealed that CFL-covered GNPs quickly form small aggregates and gradually grow to larger GNVs (ca. 200 nm), but no gradual growth was observed for SCFL-covered GNPs. This result indicated that the electrostatic repulsion inhibits fusion of the small GNVs. The size of the GNVs formed with the aid of CFLs was independent of the initial GNP concentration, but the extinction spectra were concentration-dependent. Electron microscopy imaging and simulations supported the defect formation in the assemblies. These results provided new insights into the vesicle formation mechanism.
  • Ryo Iida, Hideyuki Mitomo, Kenichi Niikura, Yasutaka Matsuo, Kuniharu Ijiro
    Small 14 14 1704230  2018年04月05日 [査読有り][通常論文]
     
    Gold nanorods (GNRs) coated with a single kind of ligand show thermoreponsive two-step assembly to provide a hierarchical structure. The GNRs (33 nm in length × 14 nm in diameter) coated with a hexa(ethylene glycol) (HEG) derivative form side-by-side assemblies at 30 °C (TA1) as a steady state through dehydration. By further heating to over 40 °C (TA2), larger assemblies, which are composed of the side-by-side assembled units, are formed as hierarchical structures. The dehydration temperature of the HEG derivative varies depending on the free volume of the HEG unit, which corresponds to the curvature of the GNRs. Upon heating, dehydration first occurs from the ligands on the side portions with a lower curvature, and then from the ligands on the edge portions with a higher curvature. The different sized GNRs (33 × 8 and 54 × 15 nm) also show two-step assembly. Both the TA1 and TA2 are dependent on the diameter of the GNRs, but independent of their length. This result supports that the dehydration is dependent on the free volume, which corresponds to the curvature. Anisotropic assembly focusing on differences in curvature provides new guidelines for the fabrication of hierarchical structures.
  • Taiyu Tazaki, Koshiro Tabata, Akira Ainai, Yuki Ohara, Shintaro Kobayashi, Takafumi Ninomiya, Yasuko Orba, Hideyuki Mitomo, Tetsuo Nakano, Hideki Hasegawa, Kuniharu Ijiro, Hirofumi Sawa, Tadaki Suzuki, Kenichi Niikura
    RSC Advances 8 30 16527 - 16536 2018年 [査読有り][通常論文]
     
    Intranasal inactivated influenza vaccines can elicit mucosal immune responses that protect against virus infection. For the development of intranasal inactivated influenza vaccines, effective adjuvants inducing minimal adverse reactions are required. Generally, however, lower toxicity adjuvants have lower adjuvanticity. In this research, we fabricated nanoparticle-based adjuvants to enhance its adjuvanticity. Herein, we focused on low-molecular-weight polyinosinic-polycytidylic acid, referred to as uPIC(40:400), as a weak and less toxic RNA adjuvant. We conjugated uPIC(40:400) with different shaped gold nanoparticles (AuNPs) electrostatically. Conjugation with gold nanorods, but not spherical AuNPs, markedly enhanced the adjuvanticity of uPIC(40:400), leading to the suppression of viral infection in mice. Notably, conjugation with gold nanorods did not increase the inflammatory cytokine production in dendritic cells. These data indicated that gold nanorods can provide a good platform for enhancing the weak adjuvanticity of uPIC(40:400) while maintaining low inflammatory cytokine production toward the development of intranasal inactivated influenza vaccines.
  • Jinjian Wei, Kenichi Niikura, Hideyuki Mitomo, Yasutaka Mastuo, Kuniharu Ijiro
    JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 17 12 9149 - 9156 2017年12月 [査読有り][通常論文]
     
    We demonstrate that gold nanoparticles (GNPs) can spontaneously self-assemble to form hollow structures in the presence of sugar-terminated fluorinated-oligo(ethylene glycol) ligands. The size of the fabricated gold nanoparticle vesicles (GNVs) was dependent on the solvent properties, the number of glucose units at the terminal of the surface ligands, and the initial GNP concentration. Time-dependent studies showed that quick aggregation and subsequent slow fusion were involved in the GNV formation in solution.
  • Kuniharu Ijiro, Hideyuki Mitomo
    POLYMER JOURNAL 49 12 815 - 824 2017年12月 [査読有り][通常論文]
     
    Among the many important biopolymers, DNA has been a key component in material sciences and nanotechnology. We have focused on the fabrication of metal nanoarchitectures using DNA as a template due to its intrinsic properties and advantages, such as a well-ordered structure, rich chemical functionality and programmable base-pairing interactions, as well as the availability of multiple enzymes for DNA manipulation. In this review, various methods for the fabrication of DNA-templated metal nanoarchitecture are introduced. The methods include DNA-mediated metal nanoparticle formation, DNA-templated conductive nanowire fabrication by metal depositions, sequence-selective metal deposition onto DNA for elaborate nanowire fabrication and DNA brushes as templates for use on solid substrates. DNA sequence-selective binding of metal ions and metal complexes and subsequent reduction to metals are fundamental issues for the fabrication of metal nanoarchitectures. The resultant metal nanoparticles and their assemblies can be used as functional nanomaterials in applications such as catalysts, conducting nanowires, optical nanomaterials and especially in metamaterials. This biopolymer-templating method can be applied not only to metal deposition but also to the assembly of functional molecules.
  • Hideyuki Mitomo, Satoshi Nakamura, Yasunobu Suzuki, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 17 12 8995 - 9001 2017年12月 [査読有り][通常論文]
     
    In this study, we have prepared double-stranded DNA brushes on glass or quartz substrates through the immobilization of biotinylated oligo-DNA, followed by hybridization and polymerization of the DNA by a surface-initiated enzymatic polymerization method. The density of the DNA brush was calculated based on UV spectra and agarose gel electrophoresis. Prepared DNA brushes showed a relatively high density of DNA chains (over 1500 chains/mu m(2)) independent of the length of the DNA. Atomic force microscopy of the 2D-patterned DNA brushes indicated dynamic changes in height under various salt concentrations. These results provided insight into the conformation of DNA brushes.
  • Guoqing Wang, Yiding Liu, Chuanbo Gao, Lei Guo, Miaofang Chi, Kuniharu Ijiro, Mizuo Maeda, Yadong Yin
    CHEM 3 4 678 - 690 2017年10月 [査読有り][通常論文]
     
    Manipulating the growth mode of colloidal nanocrystals is of both fundamental interest and technological importance because it is often connected to the control of their shape, morphology, and physicochemical properties. In conventional wisdom, island growth during thin-film deposition is restricted to lattice-mismatched materials. Here, we show that deposition of Au on Au nanostructures (e.g., nanoplates, nanorods, and nanospheres) can produce separate Au islands on the seed surface with tunable size and density while preserving the original crystal structure. The island growth in the system is ascribed to the synergistic effect of fast redox kinetics and surface capping of large polymeric ligands. Decreasing the reaction rate or changing the capping ligands could readily transform the deposition of Au on Au nanostructures from island growth to layer-by-layer mode. We further take advantage of the dense hotspots of the islands-on-plate nanostructures and demonstrate their excellence in surface-enhanced Raman scattering detection.
  • Yu Torii, Naotoshi Sugimura, Hideyuki Mitomo, Kenichi Niikura, Kuniharu Ijiro
    LANGMUIR 33 22 5537 - 5544 2017年06月 [査読有り][通常論文]
     
    Stimuli-responsive assembly of gold nanoparticles (AuNPs) with precise control of the plasmonic properties, assembly size, and stimuli responsivity has shown potential benefits with regard to biosensing devices and drug-delivery systems. Here we present a new pH-responsive coassembly system of oligo(ethylene glycol) (OEG)-coated AuNPs with anionic polymers as an external mediator via hydrogen bonding in water. Hydrogen-bond-driven coassemblies of OEG-AuNPs with poly(acrylic acid) (PAA) were confirmed by the monitoring of plasmonic peaks and hydrodynamic diameters. In this system, the protonation of anionic polymers on change in pH triggered the formation of hydrogen bond between the OEG-AuNPs and polymers, providing sensitive pH responsivity. The plasmonic properties and assembly size are affected by both the ratio of PAA to AuNPs and the molecular weight of PAAs. In addition, the attachment of hydrophobic groups to the surface ligand or anionic polymer changed the responsive pH range. These results demonstrated that the coassembly with an external mediator via hydrogen bonding provides a stimuli-responsive assembly system with tunable plasmonic properties, assembly size, and stimuli responsivity.
  • Satoshi Nakamura, Hideyuki Mitomo, Miho Aizawa, Takeharu Tani, Yasutaka Matsuo, Kenichi Niikura, Andrew Pike, Masayuki Naya, Atsushi Shishido, Kuniharu Ijiro
    ACS Omega 2 5 2208 - 2213 2017年05月31日 [査読有り][通常論文]
     
    Control over the orientation of metal nanorods is important for both fundamental and applied research. We show that gold nanorods (GNRs) can be aligned in a single direction by adsorbing positively charged GNRs onto a double-strand DNA-grafted substrate through electrostatic interaction. The ordered structure can be optimized by controlling the density of the positive charges on the surface of the GNRs. We found, in agreement with the results of theoretical simulation, that the resultant structure exhibits plasmonic properties that are dependent on the GNR orientation relative to the direction of an oscillating electric field. Our approach provides new insights into the polymer-assisted self-assembly of rod-shaped nanoparticles utilizing electrostatic interactions.
  • Ken-Ichi Sano, Kanako Iijima, Norihisa Nakayama, Kuniharu Ijiro, Yoshihito Osada
    CHEMISTRY LETTERS 46 5 719 - 721 2017年05月 [査読有り][通常論文]
     
    Cell-penetrating peptides (CPPs) as carriers for the intracellular delivery of various proteins and macromolecules have been studied extensively. Nonetheless, the delivery efficiency is relatively low. We showed previously that a rigid and fibrous cationic coiled-coil protein, CCPC 140, has cell-penetrating activity superior to that of reported CPPs. In this report, we exploited CCPC 140 for the intracellular delivery of the green fluorescent protein (GFP). The activity of CCPC 140 for intracellular delivery of GFP was compared with an octa-arginine peptide, a typical CPP that is widely used. The cellular delivery of proteins by CCPC 140 was >20-fold more efficient than that of octa-arginine. These results indicate that CCPC 140 has significant potential for delivery of proteins to cells.
  • Katsuyuki Nambara, Kenichi Niikura, Hideyuki Mitomo, Takafumi Ninomiya, Chie Takeuchi, Jinjian Wei, Yasutaka Matsuo, Kuniharu Ijiro
    LANGMUIR 32 47 12559 - 12567 2016年11月 [査読有り][通常論文]
     
    Gold nanoparticles (GNPs) show promise as both drug and imaging carriers with applications in both diagnosis and therapy. For the safe and effective use of such gold nanomaterials in the biomedical field, it is crucial to understand how the size and shape of the nanomaterials affect their biological features, such as in vitro cellular uptake speed and accumulation as well as cytotoxicity. Herein, we focus on triangular gold nanoparticles (TNPs) of four different sizes (side length 46, 55, 72, and 94 nm; thickness 30 nm) and compare the cellular internalization efficiency with those of spherical nanoparticles (SNPs) of various diameters (22, 39, and 66 nm). Both surfaces were coated with anionic thiol ligands. Inductively coupled plasma emission spectrometry (ICP-ES) data demonstrated that TNPs with longer sides showed higher levels of uptake into RAW264.7 and HeLa cells. On the other hand, in the case of SNPs, those with smaller diameters showed higher levels of uptake in both cells. Our results support the notion of a reverse size dependence of TNPs and SNPs in terms of cellular uptake. For HeLa cells, in particular, 20-fold more efficient internalization was observed for TNPs with longer sides (72 nm side length) compared to SNPs (66 nm) with a similar surface area. These results highlight the importance of the shape of nanomaterials on their interactions with cells and provide a useful guideline for the use of TNPs.
  • Ryo Iida, Hideyuki Mitomo, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    JOURNAL OF PHYSICAL CHEMISTRY C 120 29 15846 - 15854 2016年07月 [査読有り][通常論文]
     
    This paper presents the thermoresponsive assembly behaviors of gold nanoparticles (AuNPs; 3, 5, and 10 nm in diameter) that are coated with a self-assembled monolayer of oligo(ethylene glycol) (OEG) ligands terminated with alkyl heads. AuNPs (5 nm in diameter) coated with OEG ligands without an alkyl head did not assemble within a temperature range from 20 to 70 degrees C. However, AuNPs coated with ethyl, iso-propyl, and propyl-headed OEG AuNPs afforded assembly at temperatures of 56, 33, and 19 degrees C, respectively, indicating that the assembly temperature can be tuned over a wide range by slight changes in the hydrophobicity of the alkyl head. Almost no hysteresis during the heating/cooling cycles was observed for the assembly/disassembly process. The diameter of the AuNPs also affected the assembly temperature, with increases in the diameter of the AuNP affording a lower assembly temperature. The ligand with the shorter alkyl tail length provided the lower assembly temperature of AuNPs than the ligand with longer tail.
  • Jinjian Wei, Kenichi Niikura, Takeshi Higuchi, Takashi Kimura, Hideyuki Mitomo, Hiroshi Jinnai, Yasumasa Joti, Yoshitaka Bessho, Yoshinori Nishino, Yasutaka Matsuo, Kuniharu Ijiro
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138 10 3274 - 3277 2016年03月 [査読有り][通常論文]
     
    We demonstrate that binary mixtures of small and large gold nanoparticles (GNPs) (5/15, 5/30, 10/30, and 15/30 nm in diameter) in the presence of a glucose-terminated fluorinated oligo(ethylene glycol) ligand can spontaneously form size-segregated assemblies. The outermost layer of the assembly is composed of a single layer of small-sized GNPs, while the larger-sized GNPs are located in the interior, forming what is referred to as a yolk/shell assembly. Time course study reveals that small and large GNPs aggregate together, and these kinetically trapped aggregations were transformed into a size-segregated structure by repeating fusions. A yolk/shell structure was directly visualized in solution by X-ray laser diffraction imaging, indicating that the structure was truly formed in solution, but not through a drying process.
  • Hideyuki Mitomo, Kenta Horie, Yasutaka Matsuo, Kenichi Niikura, Takeharu Tani, Masayuki Naya, Kuniharu Ijiro
    ADVANCED OPTICAL MATERIALS 4 2 259 - 263 2016年02月 [査読有り][通常論文]
  • Hideyuki Mitomo, Asumi Eguchi, Yasunobu Suzuki, Yasutaka Matsuo, Kenichi Niikura, Kohji Nakazawa, Kuniharu Ijiro
    JOURNAL OF BIOMEDICAL NANOTECHNOLOGY 12 2 286 - 295 2016年02月 [査読有り][通常論文]
     
    In conventional cell culture systems, trypsin is generally used for cell harvesting. However, trypsin damages the cells due to the nonselective degradation of proteins on the cell surface. This is a critical issue for cell culture systems. Therefore, an alternative cell culture system with the lowest possible impact on cells is desired. In this paper, we have focused on DNA as a sacrificial layer and DNase as an alternate enzyme instead of trypsin. DNase ought not to result in damage to or stress on cells as it only hydrolyzes DNAs while the plasma membrane and extracellular matrices are basically composed of lipids, proteins, and glycosides. Therefore, we fabricated DNA-grafted substrates as cell culture dishes and evaluated this novel cell culture system. As a result, we were able to culture several types of mammalian cells on the DNA-grafted substrates, with the cells harvested using DNase with only little damage to the cells. This cell culture system could provide a breakthrough in cell culturing technology.
  • 三友秀之, 新倉謙一, 居城邦治
    高分子論文集 73 2 147 - 156 2016年 [査読有り][通常論文]
     
    In recent years, self-assembly beyond the molecule, which combines biological chemistry, materials science and nano- or micro-meter scale technology, has attracted much attention. Fundamental research on the self-assembly of non-molecular systems such as metal nanoparticles, which are regarded as "artificial molecules'', can enhance our understanding of the concept of self-assembly. Herein, we propose a robust strategy for the dimension-controllable fabrication of nano-assemblies of nanoparticles through tuning inter-particle interactions using suitable surface ligands. The formation of hydrogels consisting of a fibrous assembly of quantum dots (QDs), multi-layered gold nanoparticles (AuNPs), and AuNP vesicles as well as their prospective applications are investigated. The development of AuNP vesicles with hollow structures and special optical properties motivated by biomimetics has been extensively explored in medicinal chemistry for potential application to drug delivery systems (DDSs) and as a platform for surface-enhanced Raman scattering as an analytical tool. Novel self-assembly strategies using Janus-like nanoparticles are also discussed.
  • Guoqing Wang, Shengyang Tao, Yiding Liu, Lei Guo, Guohui Qin, Kuniharu Ijiro, Mizuo Maeda, Yadong Yin
    CHEMICAL COMMUNICATIONS 52 2 398 - 401 2016年 [査読有り][通常論文]
     
    We communicate an unconventional synthesis of Au nanoplates with high yield and excellent reproducibility through polyvinylpyrrolidone (PVP)-assisted H2O2 reduction. Unlike the ones prepared using halide-based surfactants, the PVP-capped Au nanoplates are found to afford fairly easy bio-functionalization, suggesting a vastly expanded spectrum of applications in bio-related fields.
  • Norihisa Nakayama, Kyoji Hagiwara, Yoshihiro Ito, Kuniharu Ijiro, Yoshihito Osada, Ken-ichi Sano
    LANGMUIR 31 30 8218 - 8223 2015年08月 [査読有り][通常論文]
     
    Numerous cationic peptides that penetrate cells have been studied intensively as drug delivery system carriers for cellular delivery. However, cationic molecules tend to be cytotoxic and cause inflammation, and their stability in the blood is usually low. We have previously demonstrated that a rigid and fibrous cationic coiled-coil protein exhibited cell-penetrating ability superior to that of previously reported cell-penetrating peptides. Making use of structural properties, here we describe the cell-penetrating activity of a rigid and fibrous coiled-coil protein with a noncationic surface. A fibrous coiled-coil protein of pI 6.5 penetrated 100% of the cells tested in vitro at a concentration of 500 nM, which is comparable to that of previously reported cell-penetrating peptides. We also investigated the effect of cell-strain dependency and short-term cytotoxicity.
  • Guoqing Wang, Hideyuki Mitomo, Yasutaka Matsuo, Kenichi Niikura, Mizuo Maeda, Kuniharu Ijiro
    JOURNAL OF COLLOID AND INTERFACE SCIENCE 452 224 - 234 2015年08月 [査読有り][通常論文]
     
    Solution-phase synthesis and post-synthetic bio-modification have continued to play a dominant role in preparation of nanostructured biomaterials. Heterogeneous nucleation and growth that occur much more often in nature, however, remain rarely explored in nano-biomaterials research. We have newly developed a DNA-modulated photoconversion approach to uniform silver nanoparticles that afford DNA-directed recognition and multi-mode imaging. The present study was aimed at understanding the rapid heterogeneous nucleation and growth of AgNPs at the solid-liquid interface with the aid of DNA. Dynamic changes in absorbance, size and morphology of silver nanostructures were monitored and analyzed to clarify the growth kinetics, which indicated a synthetic route involving synchronous growth of silver nanostructures and the fragmentation and consumption of AgCl. Various stabilizers, including polymer and amino acids, were assessed and compared with respect to the efficacy in photoconversion of AgCl. DNA was found to offer the best monodispersity and the smallest diameter for the resultant AgNPs, due to its strong interactions to silver species as well as excellent charge dispersion ability. By controlling the physicochemical property of DNA through choice of pH and ionic strength, we have demonstrated tunable structure and composition of the nanoparticles. (C) 2015 Elsevier Inc. All rights reserved.
  • Ryo Iida, Hitoshi Kawamura, Kenichi Niikura, Takashi Kimura, Shota Sekiguchi, Yasumasa Joti, Yoshitaka Bessho, Hideyuki Mitomo, Yoshinori Nishino, Kuniharu Ijiro
    LANGMUIR 31 14 4054 - 4062 2015年04月 [査読有り][通常論文]
     
    This study aims at the synthesis of Janus gold nanoparticles (Janus GNPs) with hydrophilic/hydrophobic faces by a simple ligand exchange reaction in an homogeneous system and at the elucidation of the self-assembled structures of the Janus GNPs in water. As hydrophilic surface ligands, we synthesized hexaethylene glycol (E6)-terminated thiolate ligands with C3, C7, or C11 alkyl chains, referred to as E6C3, E6C7, and E6C11, respectively. As a hydrophobic ligand, a butyl-headed thiolate ligand C4-E6C11, in which a C4 alkyl was introduced on the E6C11 terminus, was synthesized. The degree of segregation between the two ligands on the GNPs (5 nm in diameter) was examined by matrix-assisted laser desorption/ionization time-of fright mass spectrometry (MALDI-TOF MS) analysis. We found that the choice of immobilization methods, one-step or two-step addition of the two ligands to the GNP solution, crucially affects the degree of segregation. The two-step addition of a hydrophilic ligand (E6C3) followed by a hydrophobic ligand (C4-E6C11) produced a large degree of segregation on the GNPs, providing Janus-like GNPs. When dispersed in water, these Janus-like GNPs formed assemblies of similar to 160 nm in diameter, whereas Domain GNPs, in which the two ligands formed partial domains on the surface, were precipitated even when the molar ratio of the hydrophilic ligand and the hydrophobic ligand on the surface of the NPs was almost 1:1. The assembled structure of the Janus-like GNPs in water was directly observed by pulsed coherent X-ray solution scattering using an X-ray free-electron laser, revealing irregular spherical structures with uneven surfaces.
  • Norihisa Nakayama, Kyoji Hagiwara, Yoshihiro Ito, Kuniharu Ijiro, Yoshihito Osada, Ken-Ichi Sano
    LANGMUIR 31 9 2826 - 2832 2015年03月 [査読有り][通常論文]
     
    Molecules with structural anisotropy and rigidity, such as asbestos, demonstrate high cell-penetrating activity but also high toxicity. Here we synthesize a biodegradable, rigid, and fibrous artificial protein, CCPC 140, as a potential vehicle for cellular delivery. CCPC 140 penetrated 100% of cells tested in vitro, even at a concentration of 3.1 nM-superior to previously reported cell-penetrating peptides. The effects of cell-strain-dependency and aspect ratio on the cell-penetrating activity of CCPC 140 were also investigated.
  • Hideyuki Mitomo, Yukie Watanabe, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    CHEMISTRY-AN ASIAN JOURNAL 10 2 455 - 460 2015年02月 [査読有り][通常論文]
     
    DNA molecules have come under the spotlight as potential templates for the fabrication of nanoscale products, such as molecular-scale electronic or photonic devices. Herein, we report an enhanced approach for the synthesis of oligoblock copolymer-type DNA by using the Klenow fragment exonuclease minus of E. coli DNA polymerase I (KF-) in a multi-step reaction with natural and unnatural nucleotides. First, we confirmed the applicability of unnatural nucleotides with 7-deaza-nucleosides-which was expected because they were non-metalized nucleotides-on the unique polymerization process known as the "strand-slippage model". Because the length of the DNA sequence could be controlled by tuning the reaction time, analogous to a living polymerization reaction on this process, stepwise polymerization provided DNA block copolymers with natural and unnatural bases. AFM images showed that this DNA block copolymer could be metalized sequence-selectively. This approach could expand the utility of DNA as a template.
  • Akinori Kuzuya, Masafumi Kaino, Mirai Hashizume, Kazuki Matsumoto, Takeaki Uehara, Yasutaka Matsuo, Hideyuki Mitomo, Kenichi Niikura, Kuniharu Ijiro, Yuichi Ohya
    POLYMER JOURNAL 47 2 177 - 182 2015年02月 [査読有り][通常論文]
     
    A box-shaped' three-dimensional (3D) DNA origami of similar to 40-nm dimensions was selectively formed by closing a symmetric open motif with three orthogonal faces. This 3D DNA origami was used as an intelligent nano-container to encapsulate exactly one 10-nm gold nanoparticle (AuNP). AuNPs were functionalized with thiol-modified DNA strands and attached to one of the faces of the open motif, which was designed to be an interior surface of the box and decorated with three complementary strands. The open motif was then closed into the box shape as triggered by the addition of DNA strands joining the remaining edges. An examination of the suitable folding path of an M13 scaffold using fluorescently labeled staple strands revealed that the flexibility at the hinge was essential for the efficient closing of the DNA origami container. Atomic force microscope and transmission electron microscope imaging of agarose-gel-purified complexes clearly showed the successful encapsulation of one AuNP inside the shell.
  • Kuniharu Ijiro
    NANOBIOSYSTEMS: PROCESSING, CHARACTERIZATION, AND APPLICATIONS VIII 9557 2015年 [査読有り][通常論文]
  • Kenichi Niikura, Kenya Kobayashi, Chie Takeuchi, Naoki Fujitani, Shuko Takahara, Takafumi Ninomiya, Kyoji Hagiwara, Hideyuki Mitomo, Yoshihiro Ito, Yoshihito Osada, Kuniharu Ijiro
    ACS APPLIED MATERIALS & INTERFACES 6 24 22146 - 22154 2014年12月 [査読有り][通常論文]
     
    The nanoparticle-based delivery of siRNA with a noncationic outermost surface at a low particle concentration is greatly desired. We newly synthesized a bifurcated ligand (BL) possessing hydrophobic and hydrophilic arms as a surface ligand for gold nanoparticles (AuNPs) to allow siRNA delivery. The concept underlying the design of this ligand is that amphiphilic property should allow AuNPs to permeate the cell cytosol thorough the endosomal membrane. BLs and quaternary cationic ligands were codisplayed on 40 nm AuNPs, which were subsequently coated with siRNA via electrostatic interaction. The number of siRNAs immobilized on a single nanoparticle was 26, and the conjugate showed a negative zeta potential due to siRNAs on the outermost surface of the AuNPs. Apparent gene silencing of luciferase expression in HeLa cells was achieved at an AuNP concentration as low as 60 pM. Almost no gene silencing was observed for AuNPs not displaying BLs. To reveal the effect of the BL, we compared the number of AuNPs internalized into HeLa cells and the localization in the cytosol between AuNPs displaying and those not displaying BLs. These analyses indicated that the role of BLs is not only the simple promotion of cellular uptake but also involves the enhancement of AuNPs permeation into the cytosol from the endosomes, leading to effective gene silencing.
  • 慢性腎臓病に伴う骨・ミネラル代謝異常(CKD-MBD)の骨質の解析
    木村–須田廣美, 金沢恭祐, 伊藤哲平, 日高公介, 植野秀俊, 居城邦治, 小林幸雄, 圦本尚義
    北海道骨粗鬆症研究会雑誌 3 2 12 - 14 2014年10月 [査読有り][通常論文]
  • Kenya Kobayashi, Jinjian Wei, Ryo Iida, Kuniharu Ijiro, Kenichi Niikura
    POLYMER JOURNAL 46 8 460 - 468 2014年08月 [査読有り][通常論文]
     
    Nanoparticles with a diameter of <100 nm are regarded as potential medical materials, as this size allows nanoparticles to circulate in vivo and possibly reach targeted tumors. Inorganic nanoparticles in particular are able to interact with light and/or magnetic fields, thus extending their potential applications to such fields as fluorescence labeling, magnetic resonance imaging and stimulus-responsive drug delivery that are essential to the diagnosis and treatment of disease. To facilitate their use in such applications, the appropriate design of surface ligands on these nanoparticles is necessary. The surface ligands determine the physicochemical properties of the surface, such as hydrophilicity/hydrophobicity and zeta potential as well as dispersibility in solution. These properties have an especially important role in determining nanoparticle cell associations, such as cellular membrane permeability, immune responses and localization in vivo. This review focuses on recent advances in the surface engineering of nanoparticles for therapeutic applications.
  • Ryuzo Kawamura, Ken-Ichi Sano, Kuniharu Ijiro, Yoshihito Osada
    RSC ADVANCES 4 62 32953 - 32959 2014年 [査読有り][通常論文]
     
    Biomolecular motors have cooperative functions that facilitate various important cellular functions such as signaling and deformation. However, the multiple-molecular behavior is poorly understood when compared with the well-studied behavior of single molecules. Kinesin and microtubules (MTs) are a combination of motor and rail proteins that have been reported to show cooperativity in moving patterns. Here, we report that cross-linking of isotropic MTs enhances the movement of the local network temporally, which can elicit the effective conveyance of 5 mu m diameter silica microbeads. The average velocity of the beads reached 143 nm s(-1) for over 15 min, which is 2.7 times higher than the beads on kinesin-driven MTs without cross-links. Although the velocity of the beads fluctuated over the time course, the maximum velocity calculated from 5 s displacement reached 1.2 mu m s(-1), which was ca. 3-fold higher than the intrinsic driving velocity of kinesins, i.e., the sliding velocity of the MTs without cross-links. This technique provides such an enhanced movement by simply cross-linking the isotropic MTs, but without specific control or alignment over network polarity. The enhancement in the local motion of the MTs is discussed in terms of the "mechanochemical" effect coupled between dynamically stored elastic energies in the MT network and the collective motion of MTs driven by an ATP-fueled kinesin motor.
  • Kenya Kobayashi, Kenichi Niikura, Chie Takeuchi, Shota Sekiguchi, Takafumi Ninomiya, Kyoji Hagiwara, Hideyuki Mitomo, Yoshihiro Ito, Yoshihito Osada, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 50 10 1265 - 1267 2014年 [査読有り][通常論文]
     
    Gold nanoparticles (AuNPs) coated with ester-headed or ether-headed PEG ligands were synthesized. Ester-headed AuNPs, but not ether-headed, were transferred from the organic phase (CH2Cl2) to the alkali aqueous phase, indicating that the hydrolysis of the ester moiety triggered the phase transfer of the AuNPs. We found that AuNPs with ester-headed ligands (ester-AuNPs) were internalized into HeLa cells at a greater level than were ether-headed AuNPs.
  • Guoqing Wang, Hideyuki Mitomo, Yasutaka Matsuo, Naonobu Shimamoto, Kenichi Niikura, Kuniharu Ijiro
    Journal of Materials Chemistry B 1 43 5899 - 5907 2013年12月21日 [査読有り][通常論文]
     
    Silver halide (AgX, X = Cl, Br, I)-based materials represent an emerging class of heterogeneous photocatalysts. Despite progress in the synthesis of carrier-separated AgX-based photocatalysts, a number of issues remain unaddressed, including complicated synthesis, unfavorably large size and therefore poor photocatalytic performance of the resultant structures. Here we show the one-step DNA-programmable synthesis of Ag/AgCl nanostructures that takes only approximately 1 min for photocatalytic application. The optimal DNA-encapsulated structures show DNA sequence-specific sizes down to less than 40 nm with a Ag/AgCl composition ratio of 2:1, affording a vastly increased surface area and higher photocatalytic activity than any Ag/AgX nanostructures reported previously by over two orders of magnitude. From a physical standpoint, importantly, the plasmonic nanostructured silver in Ag/AgCl accelerates the photocatalytic reaction in terms of fast electron injection to AgCl, leading to enhanced hole-electron separation and high-performance photocatalysis under visible light. To test the effect of DNA encapsulation on the Ag/AgCl nanostructures, both positively and negatively charged organic compounds serve as the model pollutants to assess their photocatalytic selectivity. Our results show that the photodecomposition of the positively charged compounds obeys a first-order rate law, whereas the negatively charged compound is decomposed with zero-order kinetics. This comparison offers a mechanistic insight into reaction kinetics on the DNA-encapsulated photocatalyst. We further find that the DNA-encapsulated Ag/AgCl photocatalysts are robust and can be recycled. To extend the applicability of the Ag/AgCl nanostructures, their use in the efficient photocatalytic inactivation of cancer cells is also demonstrated for the first time, opening up a new avenue to daylight-based theranostics. © 2013 The Royal Society of Chemistry.
  • Daisuke Ishii, Hiroko Horiguchi, Yuji Hirai, Hiroshi Yabu, Yasutaka Matsuo, Kuniharu Ijiro, Kaoru Tsujii, Tateo Shimozawa, Takahiko Hariyama, Masatsugu Shimomura
    SCIENTIFIC REPORTS 3 3024  2013年10月 [査読有り][通常論文]
     
    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair-and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.
  • 三友秀之, 渡辺雪江, 松尾保孝, 新倉謙一, 居城邦治
    高分子論文集 70 7 337 - 340 2013年07月 [査読有り][通常論文]
     
    Top-down processes, such as photolithography, have been approaching a limit with regard to the fabrication of fine structures. For the preparation of molecular-scale fine structures, it is important that conventional self-assembly methods should be adapted to a "programmable self-assembly" as a next-generation bottom-up system. We aim to fabricate nano-gap electrodes by sequence-selective metallization of template DNA. We have already reported the fabrication of sequence-selective platinum nano-wires using poly(guanine) and poly(adenine-thymine) diblock DNA, which is enzymatically polymerized as a template. That method, however, cannot be extended to the preparation of oligoblock DNA. In this study, we prepared triblock DNA sequences using guanine as a platinum-binding natural nucleotide and 7-deaza-guanine as a platinum-nonbinding unnatural nucleotide for the construction of platinum nano-wires with nano-gap structures. ©2013, The Society of Polymer Science,.
  • Hidekazu Kumano, Hideaki Nakajima, Hitoshi Iijima, Satoru Odashima, Yasuhiro Matsuo, Kuniharu Ijiro, Ikuo Suemune
    APPLIED PHYSICS EXPRESS 6 6 062801  2013年06月 [査読有り][通常論文]
     
    We have fabricated silver microcolumnar photon reflectors to enhance the photon extraction efficiency from a quantum dot. The mechanically robust planar structure is favorable to couple to optical fibers for stable and efficient single-photon sources. A high photon extraction efficiency of up to 18% is achieved. Furthermore, strong suppression of multiphoton generation is confirmed. The proposed structure is quite promising toward the implementation of practical quantum key distribution systems with dot-fiber-coupled photon sources. (C) 2013 The Japan Society of Applied Physics
  • Kenichi Niikura, Tatsuya Matsunaga, Tadaki Suzuki, Shintaro Kobayashi, Hiroki Yamaguchi, Yasuko Orba, Akira Kawaguchi, Hideki Hasegawa, Kiichi Kajino, Takafumi Ninomiya, Kuniharu Ijiro, Hirofumi Sawa
    ACS NANO 7 5 3926 - 3938 2013年05月 [査読有り][通常論文]
     
    This paper demonstrates how the shape and size of gold nanoparticles (AuNPs) affect immunological responses in vivo and in vitro for the production of antibodies for West Nile virus (WNV). We prepared spherical (20 and 40 nm in diameter), rod (40 x 10 nm), and cubic (40 x 40 x 40 nm) AuNPs as adjuvants and coated them with WNV envelope (E) protein. We measured anti-WNVE antibodies after inoculation of these WNVE-coated AuNPs (AuNP-Es) into mice. The 40 nm spherical AuNP-Es (Sphere40-Es) induced the highest level of WNVE-specific antibodies, while rod AuNP-Es (Rod-Es) induced only 50% of that of Sphere40-E. To examine the mechanisms of the shape-dependent WNVE antibody production, we next measured the efficiency of cellular uptake of AuNP-Es into RAW264.7 macrophage cells and bone-marrow-derived dendritic cells (BMDCs) and the subsequent cytokine secretion from BMDCs. The uptake of Rod-Es into the cells proceeded more efficiently than those of Sphere-Es or cubic WNVE-coated AuNPs (Cube-Es), suggesting that antibody production was not dependent on the uptake efficiency of the different AuNP-Es. Cytokine production from BMDCs treated with the AuNP-Es revealed that only Rod-E-treated cells produced significant levels of interleukin-1 beta (IL-1 beta) and interleukin-18 (IL-18), indicating that Rod-Es activated inflammasome-dependent cytokine secretion. Meanwhile, Sphere40-Es and Cube-Es both significantly induced inflammatory cytokine production, including tumor necrosis factor-alpha (TNF-alpha), IL-6, IL-12, and granulocyte macrophage colony-stimulating factor (GM-CSF). These results suggested that AuNPs are effective vaccine adjuvants and enhance the immune response via different cytokine pathways depending on their sizes and shapes.
  • Kenichi Niikura, Naoki Iyo, Yasutaka Matsuo, Hideyuki Mitomo, Kuniharu Ijiro
    ACS APPLIED MATERIALS & INTERFACES 5 9 3900 - 3907 2013年05月 [査読有り][通常論文]
     
    Previously, we reported gold nanoparticles coated with semi-fluorinated ligands self-assembled into gold nanoparticle vesicles (AuNVs) with a sub-100 nm diameter in tetrahydrofuran (THF).(1) Although this size is potentially useful for in vivo use, the biomedical applications of AuNVs were limited, as the vesicular structure collapsed in water. In this paper, we demonstrate that the AuNVs can be dispersed in water by cross-linking each gold nanoparticle with thiol-terminated PEG so that the cross-linked vesicles can work as a drug delivery carrier enabling light-triggered release. Rhodamine dyes or anticancer drugs were encapsulated within the cross-linked vesicles by heating to 62.5 degrees C. At this temperature, the gaps between nanoparticles open, as confirmed by a blue shift in the plasmon peak and the more efficient encapsulation than that observed at room temperature. The cross-linked AuNVs released encapsulated drugs upon short-term laser irradiation (5 min, 532 nm) by again opening the nanogaps between each nanoparticle in the vesicle. On the contrary, when heating the solution to 70 degrees C, the release speed of encapsulated dyes was much lower (more than 2 h) than that triggered by laser irradiation, indicating that cross-linked AuNVs are highly responsive to light. The vesicles were efficiently internalized into cells compared to discrete gold nanoparticles and released anticancer drugs upon laser irradiation in cells. These results indicate that cross-linked AuNVs, sub-100 nm in size, could be a new type of light-responsive drug delivery carrier applicable to the biomedical field.
  • Kenichi Niikura, Naotoshi Sugimura, Yusuke Musashi, Shintaro Mikuni, Yasutaka Matsuo, Shintaro Kobayashi, Keita Nagakawa, Shuko Takahara, Chie Takeuchi, Hirofumi Sawa, Masataka Kinjo, Kuniharu Ijiro
    Molecular BioSystems 9 3 501 - 507 2013年03月 [査読有り][通常論文]
     
    The efficient delivery of hydrophobic drugs into target cells without the use of organic solvents or chemical linkage to delivery carriers is an important theme in the biomedical and pharmaceutical field. In this study, we synthesized virus-like particles (VLPs) coupled with cyclodextrins (CDs) as hydrophobic pockets through disulfide bonds inside the VLPs, where hydrophobic drugs can be incorporated. We report here the intracellular delivery of hydrophobic dyes or drugs encapsulated in VLPs through CDs with high efficiency and their subsequent release in cells in response to glutathione. As a model anticancer drug, paclitaxel (PTX)-CD complexes were encapsulated inside VLPs and the cytotoxic drug activity of PTX loaded VLPs against NIH3T3 cells was evaluated by CCK-8 assay. PTX-loaded VLPs exhibited a dose-dependent cytotoxic effect with a 20-fold smaller IC50 than that of free PTX dissolved in DMSO. These results indicate that VLPs with removable CDs afford highly promising carriers of hydrophobic drugs without chemical modification of drugs. © 2013 The Royal Society of Chemistry.
  • Kenichi Niikura, Naotoshi Sugimura, Yusuke Musashi, Shintaro Mikuni, Yasutaka Matsuo, Shintaro Kobayashi, Keita Nagakawa, Shuko Takahara, Chie Takeuchi, Hirofumi Sawa, Masataka Kinjo, Kuniharu Ijiro
    Molecular BioSystems 9 3 501 - 507 2013年03月 [査読有り][通常論文]
     
    The efficient delivery of hydrophobic drugs into target cells without the use of organic solvents or chemical linkage to delivery carriers is an important theme in the biomedical and pharmaceutical field. In this study, we synthesized virus-like particles (VLPs) coupled with cyclodextrins (CDs) as hydrophobic pockets through disulfide bonds inside the VLPs, where hydrophobic drugs can be incorporated. We report here the intracellular delivery of hydrophobic dyes or drugs encapsulated in VLPs through CDs with high efficiency and their subsequent release in cells in response to glutathione. As a model anticancer drug, paclitaxel (PTX)-CD complexes were encapsulated inside VLPs and the cytotoxic drug activity of PTX loaded VLPs against NIH3T3 cells was evaluated by CCK-8 assay. PTX-loaded VLPs exhibited a dose-dependent cytotoxic effect with a 20-fold smaller IC50 than that of free PTX dissolved in DMSO. These results indicate that VLPs with removable CDs afford highly promising carriers of hydrophobic drugs without chemical modification of drugs. © 2013 The Royal Society of Chemistry.
  • Hiromi Kimura-Suda, Kyosuke Kanazawa, Sachio Kobayashi, Mieko Kuwahara, Teppei Ito, Naoya Sakamoto, Makoto Kajiwara, Hideyuki Yamato, Kuniharu Ijiro, Hisayoshi Yurimoto
    JOURNAL OF BONE AND MINERAL RESEARCH 28 2013年02月 [査読有り][通常論文]
  • Analysis of herbal medicine coptis by Surface Enhanced Raman scattering Spectroscopy
    Kyouji Honma, Yasutaka Matsuo, Kuniharu Ijiro, Hiromi Kimura-Suda
    Proc. of CIF’13 “Biomimetics, Photonics Sensing and Networks” Eds. O. Karthaus and M. Kawase, PWC Pub 87 - 89 2013年 [査読有り][通常論文]
  • Hiromi Kimura-Suda, Kajiwara Makoto, Sakamoto Naoya, Kobayashi Sachio, Ijiro Kuniharu, Yurimoto Hisayoshi, Yamato Hideyuki
    Journal of Oral Biosciences 55 2 61 - 65 2013年 [査読有り][通常論文]
     
    We describe the comprehensive analysis of bone quality by using the isotope microscopy, Fourier transform infrared (FTIR) imaging, and Raman spectroscopy, which are non-destructive techniques. Isotope microscopy is a novel tool for visualizing microdomains within materials through the imaging of the 3-dimensional distribution of isotopes. This technique enabled us to observe calcium metabolism in the tibiae of mice. Thus, a stable calcium isotope fed to mice was observed in the trabecular and cortical bones. FTIR and Raman spectroscopies are powerful tools for characterizing the chemical compositions of materials and provide both qualitative and quantitative information on molecular structure. An FTIR imaging system, which is an accessory for FTIR spectroscopy, provides a distribution map of functional components in the sample. The crystallinity, secondary structure of collagen, carbonate-to- phosphate ratio, and mineral-to-matrix ratio of bone can be obtained from the IR spectra extracted from the selected area of an FTIR image. Raman spectroscopy complements FTIR spectroscopy however, the Raman spectrum provides information about functional groups in a sample as well as its FTIR spectrum. The major advantage of Raman spectroscopy for bone analysis is the ability to obtain spectra with higher spatial resolution compared with those acquired using FTIR spectroscopy. Moreover, a wide range of samples, including aqueous solutions, fibers, powders, or frozen materials can be readily analyzed, without any special preparation. Raman spectroscopy generates data on crystallinity, carbonate-to-phosphate ratio, and mineral-to-matrix ratio in bone. © 2013 Japanese Association for Oral Biology.
  • Naonobu Shimamoto, Yoshito Tanaka, Hideyuki Mitomo, Ryuzo Kawamura, Kuniharu Ijiro, Keiji Sasaki, Yoshihito Osada
    ADVANCED MATERIALS 24 38 5243 - 5248 2012年10月 [査読有り][通常論文]
  • G. Wang, A. Ishikawa, A. Eguchi, Y. Suzuki, S. Tanaka, Y. Matsuo, K. Niikura, K. Ijiro
    ChemPlusChem 77 7 592 - 597 2012年07月 [査読有り][通常論文]
     
    Although progress has been made in the construction of single-electron devices (SEDs), few of the reported approaches have proved practically applicable, mainly owing to their cost-ineffectiveness and need for sophisticated instrumentation. Herein, a conceptually new method for fabricating SEDs through the metallization of divalent DNA-nanoparticle conjugates is described. Specifically, divalent DNA copolymers that are conjugated to gold nanoparticles (AuNP) were synthesized by application of the enzymatic extension of DNA conjugated on quantum-sized AuNPs. This conjugate structure allows the distance between the resulting poly(dG)-poly(dC) and the AuNP to be controlled by an ssDNA spacer. To afford poly(dG)-poly(dC) sequence-specific metal deposition, Cisplatin capable of specific chemisorption on the poly(dG)-poly(dC) is incubated with the divalent DNA copolymerAuNP conjugates, followed by reduction of the Cisplatin to Pt metal at base resolution. As a result, AuNPs separated from the Pt electrodes by the ssDNA barriers in a single conjugate could be created as a double-tunnel junction for SEDs. This study is thought to be an important step toward the programmable organization of DNA for use in SEDs.
  • Guoqing Wang, Ayako Ishikawa, Asumi Eguchi, Yasunobu Suzuki, Shukichi Tanaka, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    CHEMPLUSCHEM 77 7 592 - 597 2012年07月 [査読有り][通常論文]
     
    Although progress has been made in the construction of single-electron devices (SEDs), few of the reported approaches have proved practically applicable, mainly owing to their cost-ineffectiveness and need for sophisticated instrumentation. Herein, a conceptually new method for fabricating SEDs through the metallization of divalent DNA-nanoparticle conjugates is described. Specifically, divalent DNA copolymers that are conjugated to gold nanoparticles (AuNP) were synthesized by application of the enzymatic extension of DNA conjugated on quantum-sized AuNPs. This conjugate structure allows the distance between the resulting poly(dG)-poly(dC) and the AuNP to be controlled by an ssDNA spacer. To afford poly(dG)-poly(dC) sequence-specific metal deposition, Cisplatin capable of specific chemisorption on the poly(dG)-poly(dC) is incubated with the divalent DNA copolymerAuNP conjugates, followed by reduction of the Cisplatin to Pt metal at base resolution. As a result, AuNPs separated from the Pt electrodes by the ssDNA barriers in a single conjugate could be created as a double-tunnel junction for SEDs. This study is thought to be an important step toward the programmable organization of DNA for use in SEDs.
  • Kenichi Niikura, Naoki Iyo, Takeshi Higuchi, Takashi Nishio, Hiroshi Jinnai, Naoki Fujitani, Kuniharu Ijiro
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 18 7632 - 7635 2012年05月 [査読有り][通常論文]
     
    Gold nanoparticles (NPs) with diameters of 5, 10, and 20 nm coated with semifluorinated oligo(ethylene glycol) ligands were formed into sub-100 nm hollow NP assemblies (NP vesicles) in THF without the use of a template. The NP vesicles maintained their structure even after the solvent was changed from THF to other solvents such as butanol or CH2Cl2. NMR analyses indicated that the fluorinated ligands are bundled on the NPs and that the solvophobic feature of the fluorinated bundles is the driving force for NP assembly. The formed NP vesicles were surface-enhanced Raman scattering-active capsules.
  • Kenichi Niikura, Naoki Iyo, Takeshi Higuchi, Takashi Nishio, Hiroshi Jinnai, Naoki Fujitani, Kuniharu Ijiro
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 18 7632 - 7635 2012年05月 [査読有り][通常論文]
     
    Gold nanoparticles (NPs) with diameters of 5, 10, and 20 nm coated with semifluorinated oligo(ethylene glycol) ligands were formed into sub-100 nm hollow NP assemblies (NP vesicles) in THF without the use of a template. The NP vesicles maintained their structure even after the solvent was changed from THF to other solvents such as butanol or CH2Cl2. NMR analyses indicated that the fluorinated ligands are bundled on the NPs and that the solvophobic feature of the fluorinated bundles is the driving force for NP assembly. The formed NP vesicles were surface-enhanced Raman scattering-active capsules.
  • Shota Sekiguchi, Kenichi Niikura, Yasutaka Matsuo, Kuniharu Ijiro
    LANGMUIR 28 13 5503 - 5507 2012年04月 [査読有り][通常論文]
     
    Surface ligand molecules enabling gold nanoparticles to disperse in both polar and nonpolar solvents through changes in conformation are presented. Gold nanoparticles coated with alkyl-head-capped PEG derivatives were initially well dispersed in water through exposure of the PEG residue (bent form). When chloroform was added to the aqueous solution of gold nanoparticles, the gold nanoparticles were transferred from an aqueous to a chloroform phase through exposure of the alkyl-head residue (straight form). The conformational change (bent to straight form) of immobilized ligands in response to the polarity of the solvents was supported by NMR analyses and water contact angles.
  • Shota Sekiguchi, Kenichi Niikura, Yasutaka Matsuo, Kuniharu Ijiro
    LANGMUIR 28 13 5503 - 5507 2012年04月 [査読有り][通常論文]
     
    Surface ligand molecules enabling gold nanoparticles to disperse in both polar and nonpolar solvents through changes in conformation are presented. Gold nanoparticles coated with alkyl-head-capped PEG derivatives were initially well dispersed in water through exposure of the PEG residue (bent form). When chloroform was added to the aqueous solution of gold nanoparticles, the gold nanoparticles were transferred from an aqueous to a chloroform phase through exposure of the alkyl-head residue (straight form). The conformational change (bent to straight form) of immobilized ligands in response to the polarity of the solvents was supported by NMR analyses and water contact angles.
  • Taiki Tominaga, Ken-Ichi Sano, Jun Kikuchi, Hideyuki Mitomo, Kuniharu Ijiro, Yoshihito Osada
    ACS MACRO LETTERS 1 3 432 - 434 2012年03月 [査読有り][通常論文]
     
    The effects of water on the mechanical properties of synthetic hydrophilic polymers with double-network (DN) structures were studied under different relative humidities (RH). It was found that they could sustain nearly the same high Young's modulus as dry DN polymers in the RH range 10-80% (water content 3-17 wt 96), that is, more than 10(2) MPa. However, when the RH exceeds 80%, DN polymers abruptly absorb large amounts of water (water content 90 wt %) and transform to a highly water-swollen "gel state" with a decrease in the Young's modulus of 3 orders of magnitude. Spectroscopic analyses revealed that water molecules below RH 80% are strongly bound to hydrophilic moieties with highly restricted mobility; water under such states improves rather than reduces mechanical properties by behaving as a plasticizer. DN polymers capable of sustaining high mechanical properties, even under RH 80%, have potential uses as hydrophilic materials.
  • Taiki Tominaga, Ken-Ichi Sano, Jun Kikuchi, Hideyuki Mitomo, Kuniharu Ijiro, Yoshihito Osada
    ACS MACRO LETTERS 1 3 432 - 434 2012年03月 [査読有り][通常論文]
     
    The effects of water on the mechanical properties of synthetic hydrophilic polymers with double-network (DN) structures were studied under different relative humidities (RH). It was found that they could sustain nearly the same high Young's modulus as dry DN polymers in the RH range 10-80% (water content 3-17 wt 96), that is, more than 10(2) MPa. However, when the RH exceeds 80%, DN polymers abruptly absorb large amounts of water (water content 90 wt %) and transform to a highly water-swollen "gel state" with a decrease in the Young's modulus of 3 orders of magnitude. Spectroscopic analyses revealed that water molecules below RH 80% are strongly bound to hydrophilic moieties with highly restricted mobility; water under such states improves rather than reduces mechanical properties by behaving as a plasticizer. DN polymers capable of sustaining high mechanical properties, even under RH 80%, have potential uses as hydrophilic materials.
  • Guoqing Wang, Hirofumi Tanaka, Liu Hong, Yasutaka Matsuo, Kenichi Niikura, Masuhiro Abe, Kazuhiko Matsumoto, Takuji Ogawa, Kuniharu Ijiro
    JOURNAL OF MATERIALS CHEMISTRY 22 27 13691 - 13697 2012年 [査読有り][通常論文]
     
    The rapid development of DNA nanotechnology over the past decade has enabled the self-assembly of conducting building blocks towards the construction of conductive nanowires with potential applications in electronic nanodevices. To date, however, construction of nanostructures with novel electrical properties via DNA templating remains poorly explored. Here, we show that DNA can be used as a guiding template for the fabrication of polyaniline nanowires and gold nanoparticle (AuNP)-polyaniline-alternated hybrid nanowires, both of which exhibit novel electrical properties as characterized by point-contact current imaging atomic force microscopy (PCI-AFM). Specifically, the DNA-templated polyaniline nanowires exhibit Schottky emission-dominated conduction as well as a rectification effect, while the current-voltage (I-V) behaviours of the DNA-templated AuNP-polyaniline hybrid nanowires were found to be attributable to Coulomb blockade effects, probably due to the fact that the configuration of the hybrid nanowires resembles that of a one-dimensional array of multiple tunnel junctions. Given the facile and low-cost self-assembly technique, the present work is of fundamental and technological importance to the fabrication of one-dimensional nanodevices capable of novel charge transport.
  • Shota Sekiguchi, Kenichi Niikura, Yasutaka Matsuo, Shige H. Yoshimura, Kuniharu Ijiro
    RSC ADVANCES 2 4 1656 - 1662 2012年 [査読有り][通常論文]
     
    The nuclear pores located on the nuclear envelope work as a selective barrier to nuclear import. The transport of large cargo molecules (larger than similar to 40 kD) into the nucleus generally requires the aid of nuclear transport proteins, such as importins, which bind to nuclear localization signal (NLS) sequences in the cargo molecules and transport these molecules into the nucleus through the nuclear pore. In our previous paper, we showed that maltotriose(Glc(3))-displaying quantum dots (QDs) can pass through the nuclear pore in digitonin-treated HeLa cells. The aim of this study is to clarify the mechanism of the nuclear import of maltooligosaccharide-displaying QDs (maltooligo-QDs). We prepared maltopentaose(Glc(5)) and maltoheptaose(Glc(7))-QDs in addition to Glc(3)-QDs. The effect of the number of glucose units in the maltooligosaccharide on the rate of nuclear import of QDs has been explored by confocal laser scanning microscopy (CLSM). Further, we analyzed that the direct interactions of maltooligo-QDs to an internal protein in the nuclear pore (Nucleoporin62) using a surface plasmon resonance (SPR) system. We found that maltooligo-QDs with more than three glucose units (Glc(3), Glc(5) and Glc(7)-QDs) rapidly entered the cellular nucleus, and had a higher affinity to nucleoporin62 than those of PEG and Glc(1)-QDs. These data indicate that the interaction between nuclear pores and carbohydrates is the driving force behind the nuclear import of maltooligo-QDs.
  • Guoqing Wang, Hirofumi Tanaka, Liu Hong, Yasutaka Matsuo, Kenichi Niikura, Masuhiro Abe, Kazuhiko Matsumoto, Takuji Ogawa, Kuniharu Ijiro
    JOURNAL OF MATERIALS CHEMISTRY 22 27 13691 - 13697 2012年 [査読有り][通常論文]
     
    The rapid development of DNA nanotechnology over the past decade has enabled the self-assembly of conducting building blocks towards the construction of conductive nanowires with potential applications in electronic nanodevices. To date, however, construction of nanostructures with novel electrical properties via DNA templating remains poorly explored. Here, we show that DNA can be used as a guiding template for the fabrication of polyaniline nanowires and gold nanoparticle (AuNP)-polyaniline-alternated hybrid nanowires, both of which exhibit novel electrical properties as characterized by point-contact current imaging atomic force microscopy (PCI-AFM). Specifically, the DNA-templated polyaniline nanowires exhibit Schottky emission-dominated conduction as well as a rectification effect, while the current-voltage (I-V) behaviours of the DNA-templated AuNP-polyaniline hybrid nanowires were found to be attributable to Coulomb blockade effects, probably due to the fact that the configuration of the hybrid nanowires resembles that of a one-dimensional array of multiple tunnel junctions. Given the facile and low-cost self-assembly technique, the present work is of fundamental and technological importance to the fabrication of one-dimensional nanodevices capable of novel charge transport.
  • Shota Sekiguchi, Kenichi Niikura, Yasutaka Matsuo, Shige H. Yoshimura, Kuniharu Ijiro
    RSC ADVANCES 2 4 1656 - 1662 2012年 [査読有り][通常論文]
     
    The nuclear pores located on the nuclear envelope work as a selective barrier to nuclear import. The transport of large cargo molecules (larger than similar to 40 kD) into the nucleus generally requires the aid of nuclear transport proteins, such as importins, which bind to nuclear localization signal (NLS) sequences in the cargo molecules and transport these molecules into the nucleus through the nuclear pore. In our previous paper, we showed that maltotriose(Glc(3))-displaying quantum dots (QDs) can pass through the nuclear pore in digitonin-treated HeLa cells. The aim of this study is to clarify the mechanism of the nuclear import of maltooligosaccharide-displaying QDs (maltooligo-QDs). We prepared maltopentaose(Glc(5)) and maltoheptaose(Glc(7))-QDs in addition to Glc(3)-QDs. The effect of the number of glucose units in the maltooligosaccharide on the rate of nuclear import of QDs has been explored by confocal laser scanning microscopy (CLSM). Further, we analyzed that the direct interactions of maltooligo-QDs to an internal protein in the nuclear pore (Nucleoporin62) using a surface plasmon resonance (SPR) system. We found that maltooligo-QDs with more than three glucose units (Glc(3), Glc(5) and Glc(7)-QDs) rapidly entered the cellular nucleus, and had a higher affinity to nucleoporin62 than those of PEG and Glc(1)-QDs. These data indicate that the interaction between nuclear pores and carbohydrates is the driving force behind the nuclear import of maltooligo-QDs.
  • Keita Nagakawa, Kenichi Niikura, Tadaki Suzuki, Yasutaka Matsuo, Manabu Igarashi, Hirofumi Sawa, Kuniharu Ijiro
    CHEMISTRY LETTERS 41 1 113 - 115 2012年01月 [査読有り][通常論文]
     
    This manuscript describes the synthesis of virus capsid protein-coated Au nanoparticle (VP-AuNP) without the use of the inherent self-assembly of virus proteins into virus particles. Covalent binding between Au and cysteines in the virus proteins keep the cell-surface binding sites on the external surface. Based on this method, various sizes of VP-AuNP can be created in a similar manner to native virus particles. We clarified the optimum size of the VP-AuNP for internalization into cells.
  • Ken-Ichi Sano, Ryuzo Kawamura, Taiki Tominaga, Naoko Oda, Kuniharu Ijiro, Yoshihito Osada
    BIOMACROMOLECULES 12 12 4173 - 4177 2011年12月 [査読有り][通常論文]
     
    A chemically cross-linked filamentous actin (F-actin) gel consisting of globular actin (G-actin) as repeating units was prepared. The F-actin gel was cross-linked by covalent bonds, and the main chain is represented by the self assembly of G-actin with a high-ordered hierarchical structure. The gel. exhibited good mechanical performance with a storage modulus >1 kPa and undergoes reversible sol-gel transitions. in response to changes in the salt concentration (chemical induced sol-gel transition) as well as to shear strain (mechanical-induced sol-gel transition). Therefore, the gel exhibits self repairing ability through dynamic polymerization and depolymerization across the structure hierarchies under repeated shear stress.
  • Shota Sekiguchi, Kenichi Niikura, Naoki Iyo, Yasutaka Matsuo, Asumi Eguchi, Takakazu Nakabayashi, Nobuhiro Ohta, Kuniharu Ijiro
    ACS APPLIED MATERIALS & INTERFACES 3 11 4169 - 4173 2011年11月 [査読有り][通常論文]
     
    A simple approach to the creation of colloidal assemblies is in high demand for the development of functional devices. Here, we present the preparation of CdTe-QD (quantum dot) networks in as little as I day simply by pH modification without the use of oxidants. The QD network was tractable in water and casting from a droplet produced a porous networked film on both hydrophobic and hydrophilic solid substrates. Further, we found that citrate-protected gold nanoparticles (AuNPs, d = 5 nm) could be incorporated into the QD networks to afford a QD/Au composite network, and that the fluorescence from the QDs was largely decreased by the addition of a small proportion of AuNPs (QD:AuNP = 99.4:0.6), probably due to the efficient charge transfer through the network. These data indicate that our method is suitable for application to the creation of metal/QD hybrid materials that can be integrated into wet-based processes.
  • 平井悠司, 藪浩, 松尾保孝, 居城邦治, 下村政嗣
    表面科学 32 7 416 - 421 2011年07月 [査読有り][通常論文]
     
    6796
  • Hidetaka Akita, Tomoya Masuda, Takashi Nishio, Kenichi Niikura, Kuniharu Ijiro, Hideyoshi Harashima
    MOLECULAR PHARMACEUTICS 8 4 1436 - 1442 2011年07月 [査読有り][通常論文]
     
    The successful control of intracellular trafficking (i.e., endosomal escape and nuclear delivery) is prerequisite for the development of a gene delivery system. In the present study, we developed an in vivo hepatic gene delivery system using a plasmid DNA (pDNA) -encapsulating lipid envelope-type nanoparticle, to which we refer as a multifunctional envelope-type nanodevice (MEND). The critical structural elements of the MEND are a DNA/protamine condensed core coated with lipid bilayers including serum-resistant cationic lipids. Intravenous administration of bare MEND represents minimal transfection activity. For the surface modification of functional devices, hydrophobic moieties were chemically attached, which are shed in the spontaneous orientation outward from the MEND surface by anchoring to the lipid bilayers. Modification of the pH-dependent fusogenic peptide GALA as an endosome escape induced transfection activity by 1 and 2 orders of magnitude. In an attempt to induce the nuclear delivery of pDNA, maltotriose, a recently characterized nuclear localization signal, was additionally modified. As a result, transfection activity further enhanced by 1 order of magnitude, and it reached to the higher level obtained for a conventional lipoplex and an in vivo jetPEI-Gal, with less hepatic toxicity. The data show that the combination of GALA and maltotriose results in a highly potent functional device that shows an enhanced endosomal escape and nuclear delivery in vivo.
  • Ken-Ichi Sano, Ryuzo Kawamura, Taiki Tominaga, Hiromichi Nakagawa, Naoko Oda, Kuniharu Ijiro, Yoshihito Osada
    BIOMACROMOLECULES 12 5 1409 - 1413 2011年05月 [査読有り][通常論文]
     
    A thermoresponsive 3D microtubule hydrogel (MT gel) was prepared by simultaneous polymerization and chemical cross-linking of tubulins. The main chain of this gel is composed of cross-linked MTs, which consists of a cylindrical assembly of tubulin covalently connected by polyethylene glycol. This gel, which contains 10 mg/mL of tubulin, exhibits a storage modulus G' as high as 1 x 10(3), which is 10 times higher than the loss modulus G '' over a wide range of frequencies. The MT gel exhibits a reversible sol gel transition by temperature changes at 4-37 degrees C via depolymerization and polymerization of the MT network. Notable effects of the presence of the cross-linkage on the process of polymerization and depolymerization of tubulin were experimentally observed, and the role of the cross-linkage was discussed.
  • Kenichi Niikura, Katsuyuki Nambara, Takaharu Okajima, Ryosuke Kamitani, Shin Aoki, Yasutaka Matsuo, Kuniharu Ijiro
    ORGANIC & BIOMOLECULAR CHEMISTRY 9 16 5787 - 5792 2011年 [査読有り][通常論文]
     
    In our previous paper, secondary-amine appended cationic polymer 1 was used as a scaffold to display artificial receptors on a cell surface (R. Kamitani et al., ChemBioChem, 2009, 10, 230). This polymer can be retained on the cell surface for more than 30 min before being slowly internalized into the cells. In this study, our aim is to achieve the efficient internalization of quantum dots (QDs) into target cells via artificial receptors on the polymer. As a receptor molecule, N-acetylglucosamine (GlcNAc) moieties were introduced into the polymer, and GlcNAc binding protein-displaying QDs were used as a ligand. We found that ligand-presenting QDs could be internalized effectively into cells via polymer-mediated endocytosis, whereas QDs were not internalized into untreated cells. These data suggest that our method based on cell-surface engineering using polymers affords a new approach to the delivery of various poorly permeable nanoparticles into cells.
  • Guoqing Wang, Takashi Nishio, Masato Sato, Ayako Ishikawa, Katsuyuki Nambara, Keita Nagakawa, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 47 33 9426 - 9428 2011年 [査読有り][通常論文]
     
    We demonstrate a facile approach for converting AgCl to functional silver nanoparticles (AgNPs) via photoreduction in the presence of DNA. The resulting AgNPs are biofunctionalized, and exhibit photostable luminescence and DNA-specific Raman signatures, showing high potential for use in DNA-directed recognition and advanced bioimaging.
  • Kawamura Ryuzo, Sano Ken-ichi, Tominaga Taiki, Oda Naoko, Ijiro Kuniharu, Osada Yoshihito
    生物物理 51 S143  一般社団法人 日本生物物理学会 2011年
  • Kenichi Niikura, Katsuyuki Nambara, Takaharu Okajima, Ryosuke Kamitani, Shin Aoki, Yasutaka Matsuo, Kuniharu Ijiro
    ORGANIC & BIOMOLECULAR CHEMISTRY 9 16 5787 - 5792 2011年 [査読有り][通常論文]
     
    In our previous paper, secondary-amine appended cationic polymer 1 was used as a scaffold to display artificial receptors on a cell surface (R. Kamitani et al., ChemBioChem, 2009, 10, 230). This polymer can be retained on the cell surface for more than 30 min before being slowly internalized into the cells. In this study, our aim is to achieve the efficient internalization of quantum dots (QDs) into target cells via artificial receptors on the polymer. As a receptor molecule, N-acetylglucosamine (GlcNAc) moieties were introduced into the polymer, and GlcNAc binding protein-displaying QDs were used as a ligand. We found that ligand-presenting QDs could be internalized effectively into cells via polymer-mediated endocytosis, whereas QDs were not internalized into untreated cells. These data suggest that our method based on cell-surface engineering using polymers affords a new approach to the delivery of various poorly permeable nanoparticles into cells.
  • Guoqing Wang, Takashi Nishio, Masato Sato, Ayako Ishikawa, Katsuyuki Nambara, Keita Nagakawa, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 47 33 9426 - 9428 2011年 [査読有り][通常論文]
     
    We demonstrate a facile approach for converting AgCl to functional silver nanoparticles (AgNPs) via photoreduction in the presence of DNA. The resulting AgNPs are biofunctionalized, and exhibit photostable luminescence and DNA-specific Raman signatures, showing high potential for use in DNA-directed recognition and advanced bioimaging.
  • Kenichi Niikura, Katsuyuki Nambara, Takaharu Okajima, Yasutaka Matsuo, Kuniharu Ijiro
    LANGMUIR 26 12 9170 - 9175 2010年06月 [査読有り][通常論文]
     
    A series of FITC-labeled hydrophobic molecules (1-8) were prepared, and their cellular uptakes have been investigated using cell-cycle-synchronized HeLa cells. The cellular membrane permeability of compounds strongly depended on both the chemical structure and the cell-cycle phase. In the G1/S phase, branched hydrocarbon-containing 3 and cis-olefin-containing 2 and 8 were efficiently internalized into cells by passive diffusion. In contrast, linear alkyl chain-containing 1 and 7 were retained on the membrane without rapid internalization. In the M phase, rapid permeation was suppressed for all molecules.
  • Noriko Ohtake, Kenichi Niikura, Tadaki Suzuki, Keita Nagakawa, Shintaro Mikuni, Yasutaka Matsuo, Masataka Kinjo, Hirofumi Sawa, Kuniharu Ijiro
    CHEMBIOCHEM 11 7 959 - 962 2010年05月 [査読有り][通常論文]
  • Self-assembled Hierarchic Structures of Metal-Molecule Hybrids for Sensing and Electronic Devices
    K. Ijiro, A. Tanaka, Y. Matsuo, Y. Hashimoto, K. Nagakawa, N. Ohtake, T. Suzuki, H. Sawa, K. Niikura
    ICEP 2010 Proceedings 179 - 184 2010年05月 [査読有り][通常論文]
  • Hiroshi Yabu, Yasutaka Matsuo, Kuniharu Ijiro, Fumiaki Nishino, Toshihiko Takaki, Masahiro Kuwahara, Masatsugu Shimomura
    ACS APPLIED MATERIALS & INTERFACES 2 1 23 - 27 2010年01月 [査読有り][通常論文]
     
    Honeycomb-patterned polymer films prepared by the simple casting of a polymer solution under humid conditions were used as templates for metal microdot arrays formed on shrinkable polymer substrates by metal sputtering. After thermal shrinkage of the substrate, the periodicity of the metal microdots was reduced. in addition, microwrinkles were formed on the metal microdots. The wavelength and arrangement of the microwrinkles were changed with the metal sputtering time and the diameter of the metal microdots. A clear confinement effect was observed in the formation of the microwrinkles.
  • Takashi Nishio, Kenichi Niikura, Yasutaka Matsuo, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 46 47 8977 - 8979 2010年 [査読有り][通常論文]
     
    Fluorinated tetraethylene glycol-stabilized Au nanoparticles (FTEG-AuNPs) were well-dispersed in general polar organic solvents, such as methanol (MeOH) and THF. The cast film of FTEG-AuNPs on a TEM grid and a glass substrate was found to form a highly ordered 3D-superlattice assembly, whereas tetraethylene glycol-stabilized AuNPs (TEG-AuNPs) provide an amorphous AuNP aggregation. These data indicate that the fluorine feature on the surface of the FTEG-AuNPs is critical for the nanostructured assembly.
  • Yuji Hirai, Hiroshi Yabu, Yasutaka Matsuo, Kuniharu Ijiro, Masatsugu Shimomura
    NEW FRONTIERS IN MACROMOLECULAR SCIENCE 295 77 - + 2010年 [査読有り][通常論文]
     
    Self-organized honeycomb-patterned polymer films were prepared by using condensed water droplet arrays as templates. Porous polymer masks for dry etching were easily prepared on Si substrates by peeling off the honeycomb-patterned films. After dry etching, hexagonally-arranged micro-pores were formed on the surface of Si substrates.
  • Yuji Hirai, Hiroshi Yabu, Yasutaka Matsuo, Kuniharu Ijiro, Masatsugu Shimomura
    CHEMICAL COMMUNICATIONS 46 13 2298 - 2300 2010年 [査読有り][通常論文]
     
    Silver spike arrays with triangular sharp edges were prepared by using a self-organization process based on the condensation of water droplets and the vapor deposition process. Strongly enhanced Raman scattering of rhodamine 6G on the spike arrays were shown.
  • 森田 有香, 山本 貞明, 藪 浩, 伊藤 絵美子, 本望 修, 居城 邦治, 下村 政嗣
    表面科学 31 8 392 - 399 公益社団法人 日本表面科学会 2010年 [査読無し][通常論文]
     
    In order to address the question if the proliferative ability of MSCs is able to be enhanced by surface topology, mesenchymal stem cells from rat adult bone marrow (r-MSCs) were cultured on polystyrene and polybutadiene honeycomb films without cytokines for cell growth. SEM, AFM and time laps phase contrast imaging demonstrated the anomalous cellular adhesion morphology and division on the honeycomb films that have not been observed so far in vitro culture on 2 dimensional scaffolds.; r-MSCs did not spread at all keeping semispherical shape along culture and divided directly in the semispherical cell bodies. The proliferative ability on polystyrene honeycomb films was about 1.5 times higher than that on the control flat film and commercially available polystyrene culture plates, whereas the polybutadiene honeycomb films did not affect the proliferative ability. The polymer dependence of the proliferative ability might be ascribed to the stiffness of the honeycomb structure dependent on polymer. These results led us to the hypothesis that the polystyrene honeycomb films mimic the topography and stiffness of the niche for r-MSCs, inducing the characteristic cell shape and division which may be similar to those in vivo.
  • Kawamura Ryuzo, Sano Ken-Ichi, Tominaga Taiki, Ijiro Kuniharu, Osada Yoshihito
    生物物理 50 2 S46  一般社団法人 日本生物物理学会 2010年
  • Sano Ken-Ichi, Kawamura Ryuzo, Tominaga Taiki, Oda Naoko, Ijiro Kuniharu, Osada Yoshihito
    生物物理 50 2 S46 - S47 一般社団法人 日本生物物理学会 2010年
  • Yuji Hirai, Hiroshi Yabu, Yasutaka Matsuo, Kuniharu Ijiro, Masatsugu Shimomura
    CHEMICAL COMMUNICATIONS 46 13 2298 - 2300 2010年 [査読有り][通常論文]
     
    Silver spike arrays with triangular sharp edges were prepared by using a self-organization process based on the condensation of water droplets and the vapor deposition process. Strongly enhanced Raman scattering of rhodamine 6G on the spike arrays were shown.
  • Takashi Nishio, Kenichi Niikura, Yasutaka Matsuo, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 46 47 8977 - 8979 2010年 [査読有り][通常論文]
     
    Fluorinated tetraethylene glycol-stabilized Au nanoparticles (FTEG-AuNPs) were well-dispersed in general polar organic solvents, such as methanol (MeOH) and THF. The cast film of FTEG-AuNPs on a TEM grid and a glass substrate was found to form a highly ordered 3D-superlattice assembly, whereas tetraethylene glycol-stabilized AuNPs (TEG-AuNPs) provide an amorphous AuNP aggregation. These data indicate that the fluorine feature on the surface of the FTEG-AuNPs is critical for the nanostructured assembly.
  • Yuji Hirai, Hiroshi Yabu, Yasutaka Matsuo, Kuniharu Ijiro, Masatsugu Shimomura
    JOURNAL OF MATERIALS CHEMISTRY 20 48 10804 - 10808 2010年 [査読有り][通常論文]
     
    We demonstrate here a creation of a novel biomimetic bi-functional surface by using dry etching of silicon with a self-organized porous polymer. The novel silicon structures with hierarchical nanospike-array structures covered with fluorocarbons were fabricated by dry etching of silicon through the porous polymer masks. The antireflection and superhydrophobic properties were realized due to their large surface areas and low surface energies. These masks and silicon substrates offer great advantages and are suitable for various practical applications, including high efficiency solar cells.
  • 居城 邦治
    Trends in Glycoscience and Glycotechnology 21 122 335 - 344 2009年11月 [査読有り][通常論文]
     
    It has been reported that the conjugation of carbohydrate to proteins can promote the nuclear import of proteins (1-4). In this minireview, based on our recent data, we discuss the effect of carbohydrates on the nuclear import using quantum dots (QDs), with particular reference to the manner in which the chemical structure and density of carbohydrates displayed on their surface drastically affected the efficiency of QD permeation into the nucleus. Among the carbohydrates used in our study, the high-density display of maltotriose was the most efficient for the nuclear import of QDs. As it is not reliant on cytosolic factors for nuclear import, we concluded that the sugar-displaying QDs can be transported into the nucleus via passive diffusion rather than through a specific receptor-mediated pathway.
  • Kenichi Niikura, Kuniharu Ijiro, Shota Sekiguchi
    Trends in Glycoscience and Glycotechnology 21 122 335 - 344 2009年11月 [査読無し][通常論文]
     
    It has been reported that the conjugation of carbohydrate to proteins can promote the nuclear import of proteins (1-4). In this minireview, based on our recent data, we discuss the effect of carbohydrates on the nuclear import using quantum dots (QDs), with particular reference to the manner in which the chemical structure and density of carbohydrates displayed on their surface drastically affected the efficiency of QD permeation into the nucleus. Among the carbohydrates used in our study, the high-density display of maltotriose was the most efficient for the nuclear import of QDs. As it is not reliant on cytosolic factors for nuclear import, we concluded that the sugar-displaying QDs can be transported into the nucleus via passive diffusion rather than through a specific receptor-mediated pathway.
  • Kenichi Niikura, Keita Nagakawa, Noriko Ohtake, Tadaki Suzuki, Yasutaka Matsuo, Hirofumi Sawa, Kuniharu Ijiro
    BIOCONJUGATE CHEMISTRY 20 10 1848 - 1852 2009年10月 [査読有り][通常論文]
     
    We propose a new approach to optical virus detection, based on the spatial assembly of gold nanoparticles on the surface of viruses. Since JC virus-like particles (VLPs) comprise a repeating viral capsid protein that binds to sialic acid, the conjugation of sialic acid-linked Au particles with VLPs enables the spatial arrangement of Au particles on the VLP surface. This structure produced a red shift in the absorption spectrum due to plasmon coupling between adjacent Au particles, leading to the, construction of an optical virus detection system. Our system depends not on the simple cross-linking of VLPs and Au particles, but on an ordered Au structure covering the entire surface of the VLPs and can be applied to virus detection systems using the inherent ligand recognition of animal viruses.
  • Tomoya Masuda, Hidetaka Akita, Kenichi Niikura, Takashi Nishio, Masami Ukawa, Kaoru Enoto, Radostin Danev, Kuniaki Nagayama, Kuniharu Ijiro, Hideyoshi Harashima
    BIOMATERIALS 30 27 4806 - 4814 2009年09月 [査読有り][通常論文]
     
    Lipid envelope-type nanoparticles are promising carriers for gene delivery. The modification of liposomes with polyethyleneglycol (PEG) can often be useful in liposomal formation and pharmacokinetics. However, there is a dilemma concerning the use of PEG because of its poor intracellular trafficking properties. To overcome this problem, in the present study, we report on a strategy for improving the intracellular trafficking of PEG-modified lipid particles by incorporating a short PEG lipid. The findings presented here show that the incorporation of tetra(ethylene)glycol (TEG)-conjugated cholesterol into a liposome composition is useful in controlling the number of lipid envelopes, resulting in an improvement in particle uniformity with a reduced particle size. The TEG-modified lipid particles were found to enhance transfection activity by more than 100-fold. This increase is attributed to an enhancement of cellular uptake, and nuclear transcription by improving intracellular decoating. Moreover, the use of a various short PEG lipids in lipid particle formation showed a clear threshold polymerization degree (less or equal 25: PEG(1100)), for achieving stimulated transfection activity. Collectively, the use of short PEG lipid promises to be useful in developing an efficient non-viral gene vector. (C) 2009 Elsevier Ltd. All rights reserved.
  • Takashi Nishio, Kenichi Niikura, Yasutaka Mastuo, Kuniharu Ijiro
    International Journal of Nanoscience 8 1 219 - 222 2009年02月 [査読有り][通常論文]
  • Ryosuke Kamitani, Kenichi Niikura, Takaharu Okajima, Yasutaka Matsuo, Kuniharu Ijiro
    CHEMBIOCHEM 10 2 230 - 233 2009年01月 [査読有り][通常論文]
  • Yukako Fukuhira, Hiroshi Yabu, Kuniharu Ijiro, Masatsugu Shimomura
    SOFT MATTER 5 10 2037 - 2041 2009年 [査読有り][通常論文]
     
    Hexagonally packed water droplets condensed on a polymer solution are potential templates for the formation of honeycomb-patterned porous polymer films. A small number of surface-active molecules is indispensable for the stabilization of water droplets during solvent evaporation. Biocompatible surfactants; e. g., phospholipids, are required for the fabrication of biodegradable honeycomb-patterned polymer films, which can be used as novel biomedical materials, mainly in vivo. Among various kinds of phospholipids, dioleoylphosphatidylethanolamine (DOPE) has been reported to be the most suitable surfactant for the formation of honeycomb-patterned PLA films. Interfacial tension between a water droplet and the polymer solution is largely dependent on the chemical structure of the phospholipids. DOPE shows high interfacial tension, resulting in the stabilization of water droplets during solvent evaporation. Dierucoylphosphatidylcholine (DEPC) and dierucoylphosphatidylethanolamine (DEPE), both of which display high interfacial tension, were also found to be suitable biocompatible surfactants.
  • Kunita Itsuki, Tominaga Taiki, Kawamura Ryuzo, Nakagawa Hiromichi, Oda Naoko, Tsukamoto Rikako, Ijiro Kuniharu, Sano Ken-Ichi, Osada Yoshihito
    生物物理 49 S195  一般社団法人 日本生物物理学会 2009年
  • Kawamura Ryuzo, Sano Ken-Ichi, Kunita Istuki, Tominaga Taiki, Oda Naoko, Ijiro Kuniharu, Osada Yoshihito
    生物物理 49 S195  一般社団法人 日本生物物理学会 2009年
  • Yukako Fukuhira, Hiroshi Yabu, Kuniharu Ijiro, Masatsugu Shimomura
    SOFT MATTER 5 10 2037 - 2041 2009年 [査読有り][通常論文]
     
    Hexagonally packed water droplets condensed on a polymer solution are potential templates for the formation of honeycomb-patterned porous polymer films. A small number of surface-active molecules is indispensable for the stabilization of water droplets during solvent evaporation. Biocompatible surfactants; e. g., phospholipids, are required for the fabrication of biodegradable honeycomb-patterned polymer films, which can be used as novel biomedical materials, mainly in vivo. Among various kinds of phospholipids, dioleoylphosphatidylethanolamine (DOPE) has been reported to be the most suitable surfactant for the formation of honeycomb-patterned PLA films. Interfacial tension between a water droplet and the polymer solution is largely dependent on the chemical structure of the phospholipids. DOPE shows high interfacial tension, resulting in the stabilization of water droplets during solvent evaporation. Dierucoylphosphatidylcholine (DEPC) and dierucoylphosphatidylethanolamine (DEPE), both of which display high interfacial tension, were also found to be suitable biocompatible surfactants.
  • Tanaka Masaru, Sato Hirokazu, Sasaya Yugo, Horinouchi Suguru, Hotta Jun-ichi, Matsuo Yasutaka, Ijiro Kuniharu, Sasaki Keiji, Shimomura Masatsugu
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 505 457 - 468 2009年 [査読有り][通常論文]
  • Hiroshi Yabu, Ruokun Jia, Yasutaka Matsuo, Kuniharu Ijiro, Sada-aki Yamamoto, Fumiaki Nishino, Toshihiko Takaki, Masahiro Kuwahara, Masatsugu Shimomura
    ADVANCED MATERIALS 20 21 4200 - + 2008年11月 [査読有り][通常論文]
     
    Microporous films with various kinds of geometrical patterns including ellipsoids and rectangles are fabricated by using a self-organization process and shrinking. A shrinkable substrate can be used to change the shapes and sizes of honeycomb pores. The pit size can be miniaturized from several micrometers to hundreds of nanometers by repeating the shrinkage.
  • Kenichi Niikura, Shota Sekiguchi, Takashi Nishio, Tomoya Masuda, Hidetaka Akita, Yasutaka Matsuo, Kentaro Kogure, Hideyoshi Harashima, Kuniharu Ijiro
    CHEMBIOCHEM 9 16 2623 - 2627 2008年11月 [査読有り][通常論文]
  • Aya Tanaka, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro
    CHEMISTRY LETTERS 37 7 758 - 759 2008年07月 [査読有り][通常論文]
     
    The effect of 5'-phosphorylation at nicks on DNA stabilization was measured through the formation of DNA multiassemblies consisting of 40-mer half-sliding complementary oligon-cleotides, which had overlapping complementary 20-mer base sequences. 5'-Phosphorylated oligonucleotides formed longer DNA multiassemblies than 5'-hydroxylated ones. This result indicated that the 5'-phosphorylated sticky ends contribute to the stabilization of the DNA association due to the hydrogen bonds between 3'-hydroxy groups and 5'-phosphate groups at the nick positions.
  • H. Yabu, Y. Hirai, Y. Matsuo, K. Ijiro, M. Shimomura
    Macromolecular Symposia 267 100 - 104 2008年06月 [査読有り][通常論文]
  • Osamu Haruta, Yasutaka Matsuo, Yuichi Hashimoto, Kenichi Niikura, Kuniharu Ijiro
    LANGMUIR 24 6 2618 - 2624 2008年03月 [査読有り][通常論文]
     
    We investigated the molecular recognition between the amphiphile AzoAde, which is composed of azobenzene in the hydrophobic and adenine in the hydrophilic portion of the molecule, and oligonucleotides having a homogeneous base (dA(30), dT(30), dG(30), and dC(30)) at the air-water interface. On the basis of the complementary base-pairing of DNA in the duplex, orderly arrangement of AzoAde on templated dT(30) was examined using pi-A isotherm, UV-vis RAS, FT-IR RAS, and XPS measurements. Although there was little interaction between AzoAde and mismatched oligonucleotides (dA(30), dG(30) and dC(30)), AzoAde prepared on a dT(30) interacted with dT(30), subsequently forming a J-form assembly at the air-water interface. AFM observation of the LB films revealed the nanostructure of the J-formed AzoAde monolayer on the dT(30) subphase as well as the domain structures of the H-formed monolayers on the other oligonucleotide subphases. Therefore, dT(30) has a potential application as a template for assembling AzoAde at the air-water interface.
  • Tomoya Masuda, Hidetaka Akita, Takashi Nishio, Kenichi Niikura, Kentaro Kogure, Kuniharu Ijiro, Hideyoshi Harashima
    BIOMATERIALS 29 6 709 - 723 2008年02月 [査読有り][通常論文]
     
    Efficient nuclear gene delivery is essential for successful gene therapy. This study developed a novel system that mimics the mechanism of nuclear entry of adenovirus (Ad) by means of a Multifunctional Envelope-type Nano Device (MEND). In this system, plasmid DNA (pDNA) was condensed with polycation, followed by encapsulation in a lipid membrane. To target MEND to the nuclear pore complex (NPC), sugar served as a NPC-mediated nuclear targeting device was modified on the surface of the lipid envelope. This was accomplished via synthesis of a sugar-cholesterol conjugate. After binding of the MEND to the NPC, the pDNA core was transferred into the nucleus in conjunction with a breakdown of the lipid envelope. Sugar-modified MEND showed higher transfection efficiency compared with unmodified MEND, in non-dividing and dividing cells. Confocal microscopy confirmed that nuclear transfer of pDNA was improved by sugar modification of MEND. Furthermore, destabilization of the lipid envelope significantly enhanced transfection activity: therefore, nuclear-delivery efficiency was closely related to lipid envelope stability. Moreover, quantitative evaluation of cellular uptake and nuclear transfer processes by real-time PCR confirmed that the surface sugars affected nuclear transfer, but not cellular uptake. In summary, a novel system for the nuclear delivery of pDNA was successfully developed by using a sugar-modified MEND and by optimizing the lipid envelope stability. (c) 2007 Elsevier Ltd. All rights reserved.
  • Noriko Ohtake, Kenichi Niikura, Tadaki Suzuki, Keita Nagakawa, Hirofumi Sawa, Kuniharu Ijiro
    BIOCONJUGATE CHEMISTRY 19 2 507 - 515 2008年02月 [査読有り][通常論文]
     
    Herein, we present the efficient cellular uptake of immobilized virus-like particles (VLPs) made of recombinant JC virus capsid proteins. VLPs expressed in Escherichia coli were labeled with fluorescein isothiocyanate (FITC). We compared two approaches for the cellular uptake of the FITC-VLPs. In the first approach, FITC-VLPs were immobilized on a polystyrene substrate, and then NIH3T3 cells were cultured on the same substrate. In the second approach, cells were cultured on a polystyrene substrate, and FITC-VLPs were then added to the cell culture medium. Flow cytometric analysis and confocal laser microscopic observation revealed that immobilized VLPs were incorporated into the cells with higher efficiency than were the diffusive VLPs suspended in solution. The cellular uptake of VLPs on the substrate was increased in a VLP density-dependent manner. As a control, disassembling VLPs to form VP1 pentamers abolished incorporation into the cells. Displaying sialic acid on the substrate enhanced VLP density through the specific affinities between the VLPs and sialic acid, resulting in efficient incorporation into the seeded cells. These techniques can be applied to the development of novel drug delivery systems and cell microarrays not only of nucleic acids but also of small molecules and proteins through their encapsulation in VLPs.
  • Osamu Haruta, Yasutaka Matsuo, Kuniharu Ijiro
    COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS 313 595 - 599 2008年02月 [査読有り][通常論文]
     
    UV irradiation-induced fluorescence enhancement of thin films composed of azobenzene amphiphiles, C(12)AzoC(10)N(+) (AzoN(+)), was investigated. UV irradiation to Langmuir-Blodgett (LB) monolayers of AzoN(+) indicated that the fluorescence emission from an irradiated area was enhanced and the emission was independent of the aggregation structures of an azobenzene moiety. Moreover, UV irradiation to cast films of AzoN(+) revealed that the enhancement was increased by increasing the irradiation time. The fluorescence by excitation at 365 nm occurred over a wide range of wavelengths from around 400 nm to 650 nm, and the emission was not attributed to the J-aggregates of AzoN(+). The mechanism for this phenomenon has not been elucidated. It may be caused by the photo-chemical reaction of the azobenzene moiety or photo-induced specific aggregates. However, UV irradiation-induced fluorescence enhancement can be applicable to optical memory devices. (C) 2007 Elsevier B.V. All rights reserved.
  • Aya Tanaka, Yasutaka Matsuo, Yuichi Hashimoto, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 36 4270 - 4272 2008年 [査読有り][通常論文]
     
    Platinum metal was sequence-specifically deposited on the DNA block copolymer synthesized by the Klenow fragment of E. coli DNA polymerase I (3'-5' exonuclease deficient).
  • 山本貞明, 田中賢, 藪浩, 伊藤絵美子, 前田悠, 森田有香, 居城邦治, 下村政嗣
    表面 46 8 393 - 409 2008年 [査読無し][通常論文]
  • Aya Tanaka, Yasutaka Matsuo, Yuichi Hashimoto, Kuniharu Ijiro
    CHEMICAL COMMUNICATIONS 2008 36 4270 - 4272 2008年 [査読有り][通常論文]
     
    Platinum metal was sequence-specifically deposited on the DNA block copolymer synthesized by the Klenow fragment of E. coli DNA polymerase I (3'-5' exonuclease deficient).
  • Yasuyuk Tsuboi, Masayuki Nishino, Yasutaka Matsuo, Kuniharu Ijiro, Noboru Kitamura
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 80 10 1926 - 1931 2007年10月 [査読有り][通常論文]
     
    We demonstrate that phase separation of an aqueous poly(vinyl methyl ether) (PVME) solution can be triggered not only by a temperature change but also by photon pressure. A near-infrared continuous wave laser beam (lambda = 1064 nm) was focused through an objective lens into a heavy water (D2O) solution of PVME. A single PVME microparticle was produced and trapped at the focal point of the laser beam within several hundreds of seconds after switching on the laser. The origin of the microparticle formation (phase separation) is ascribed essentially to the photon force of the laser beam, and not to a rise in the local temperature, since heavy water is transparent at 1064 nm. The structures of the PVME microparticles produced by laser irradiation were studied in detail using confocal Raman microspectroscopy. Raman spectra of the microparticles and coiled/globular PVME were observed successfully over a wide wavenumber region. It was confirmed that the phase transition of the polymer chains from coiled to globular states proceeded during microparticle formation. The fundamental mechanism of photo-induced phase separation of PVME is discussed in terms of the interactions between the polymer and the photon force.
  • Ryosuke Kamitani, Kenichi Niikura, Tomohiro Onodera, Norimasa Iwasaki, Hideyuki Shimaoka, Kuniharu Ijiro
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 80 9 1808 - 1813 2007年09月 [査読有り][通常論文]
     
    We describe a graft-type modification of a solid surface to be able to immobilize unprotected carbohydrates with a desired pattern. Water soluble carbohydrate-trapping polymers were grown from a solid surface through surface-initiated polymerization. The polymerization of an N-tert-butonyloxycarbonyl (N-Boc)-protected aminooxy monomer 3 was carried out from the immobilized initiator on silicon or glass surfaces. The N-Boc protecting group was then removed in an acidic solution to generate an aminooxy group, which reacts with free carbohydrates through oxime bonds on immersion of the plate in a carbohydrate solution. Sugar attachment on the surface polymer was confirmed by using infrared reflection absorption spectroscopy (IR-RAS) and fluorescent images after sugar-specific binding of fluorescein-labeled lectin proteins. The polymer was also grafted in a desired pattern by partial UV-irradiation over a photomask, giving a new material to create carbohydrates arrays.
  • 山本貞明, 田中賢, 伊藤絵美子, 森田有香, 角南寛, 居城邦治, 下村政嗣
    表面科学 28 8 433 - 439 The Surface Science Society of Japan 2007年08月 [査読有り][通常論文]
     
    The mechanism that cells use to recognize micro-patterned topographies was clarified. First, 3D double-layer poly (ε-caprolactone) scaffolds equipped with honeycomb-patterned micro-pores ("honeycomb films") were prepared. Then, porcine aortic endothelial cells (PAECs) were cultured on these scaffolds for 1-6 h in serum-free medium. Finally, their initial spreading process was investigated by using AFM and confocal laser scanning microscopy. The attachment and spreading of PAECs on honeycomb films having either 6-or 16-μm pore diameters resulted in voids within the cell cytoplasm, which correspond with the size and location of the honeycomb micropores. The number of cells with this unique morphology decreased with increasing culture time. This dependence of morphology on film pore size and culture time suggests a spreading process of PAECs in which the cells spread trying to sense suitable sites to adhere. Using thick filopodia, the cells spread along the rim of the film and produced pores by close contact between two spreading filopodia. Evidently, these pores became filled in during culture, presumably as the cells began to reorganize their cytoplasma.
  • Kenichi Niikura, Takashi Nishio, Hidetaka Akita, Yasutaka Matsuo, Ryosuke Kamitani, Kentaro Kogure, Hideyoshi Harashima, Kuniharu Ijiro
    CHEMBIOCHEM 8 4 379 - 384 2007年03月 [査読有り][通常論文]
  • Osamu Haruta, Kuniharu Ijiro
    JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 7 3 734 - 737 2007年03月 [査読有り][通常論文]
     
    In order to assemble amphiphilic adenine having azobenzene, C12AzoC5Ade (AzoAde), at the air-water interface based on the molecular recognition of DNA, we prepared aqueous linear oligothymidylic acids, dT(n) (n = 4, 6, 8, 10, 30), subphase as templates. Surface pressure-area (pi-A) isotherms and UV-Vis reflection absorption spectra of AzoAde were measured to investigate the effect of chain length of the oligothymidylic acid on the molecular recognition by forming a complementary A-T base pair. It was showed that AzoAde did not form a stable monolayer on the dT(4) subphase and remained monomeric state. While AzoAde provided expanded monolayers and formed J-aggregates of azobenzene moieties on the dTn (n > 4) subphases even at the low molecular density. We also investigated the molecular recognition of template oligonucleoticles by comparing dT(30) with dA(30), indicating that AzoAde had not a specific interaction with dA(30) at the air-water interface due to base mismatching. The AzoAde monolayer on the dA(30) subphase gave H-aggregate from monomeric state by compressing it. On the other hand, it remained J-aggregated state on dT(30) subphase regardless of compression. It was, therefore, suggested that the linear oligothymidylic acids, dT(n) (n > 4), acted as templates for assembling AzoAde at the air-water interface.
  • A. Tanaka, Y. Matsuo, K. Ijiro
    Colloids and Surfaces A: Physicochemical and Engineering Aspects 284 246 - 249 2006年08月 [査読有り][通常論文]
     
    We synthesized poly(dG)-poly(dC) by the enzymatic extension of dG(10)-dC(10) with Klenow fragment exo(-). The length of prepared poly(dG)-poly(dC) was determined by the electrophoresis and the Langmuir-Blodgett (LB) method. Cationic amphiphile (2C(18)N(+)2C(1)) was spread on an aqueous solution of synthesized poly(dG)-poly(dC). And a formed polyion complex monolayer at the air-water interface due to the electrostatic interaction between the amphiphile and poly(dG)-poly(dC) was transferred on a glass substrate. The fluorescence images of the transferred polyion complex monolayers showed that single poly(dG)-poly(dC) molecules were stretched on the glass substrate and the lengths of the stretched molecules almost corresponded to 21,000 bp. The stretched poly (dG)-poly(dC) can be used as a sample for electric conductivity measurement and a template for spatially arranging molecules and metals. (c) 2005 Elsevier B.V. All rights reserved.
  • Noriko Ishizuka, Yuichi Hashimoto, Yasutaka Matsuo, Kuniharu Ijiro
    COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS 284 440 - 443 2006年08月 [査読有り][通常論文]
     
    Deoxyribonucleic acid (DNA) has a lot of characteristic features, e.g., anionic polyelectrolyte, molecular recognition and condensed pi electron. Therefore, it is expected to be applied as functional materials in not only biological but also physical fields. In this report, we attempted to prepare water-insoluble DNA films by mixing DNA and photolinkable polymer, aiming at the fabrication of bio-functionalized hydrogel films. For this purpose, photocrosslinkable polyvinyl alcohol (azide-unit pendant water-soluble photopolymer; AWP) was used. An aqueous DNA and AWP mixture was cast onto glass substrates. Irradiation of UV light on it for certain minutes provided a hydrogel film by photocrosslinking between DNA and AWP. When the formed hydrogel film was soaked in pure water for I day, large expansion of the film was observed. The expanded film was shrunk by soaking it in aqueous NaCl or CTAB solutions. The expansion and shrinkage mechanism of the film was attributed to the penetration of water into the gap between the film and the substrate due to osmotic pressure. This phenomenon can be applied to the fabrication of gel devices, e.g., a novel biosensor and drug delivery system. (c) 2005 Elsevier B.V. All rights reserved.
  • Osamu Haruta, Jin Nishida, Kuniharu Ijiro
    COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS 284 326 - 330 2006年08月 [査読有り][通常論文]
     
    In order to attempt the circular arrangement of chromophores directed by base pairing with cyclic oligonucleotides as template at the air-water interface, the monolayers of an amphiphilic adenine having azobenzene (AzoAde) were prepared on aqueous linear oligothymidylic acids (LinT6, LinT8, and LinT10) and corresponding cyclic oligothymidylic acids (CycT6, CycT8, and CycT10) solutions. The aggregation structures of AzoAde in the monolayers were investigated by in-situ UV-Vis reflection absorption spectroscopy. The linear oligothymidylic acids and CycT10 provided J aggregation of the azobenzene moiety in the formed monolayers even without compression of the monolayers, whereas the azobenzene moiety in the monolayers formed on CycT6 and CycT8 was isolated. Pi-A isotherms on the CycT6 and CycT8 subphases were different from those on other oligothymidylic acid subphases, indicating that particular arrangement of AzoAde was attained in the monolayers complexed with CycT6 and CycT8. It was, therefore, suggested that the azobenzene chromophore in the monolayer could be circularly arranged on the CycT6 and CycT8 templates at the air-water interface. (c) 2005 Elsevier B.V. All rights reserved.
  • Yasutaka Matsuo, Kuniharu Ijiro
    INTERNATIONAL JOURNAL OF NANOSCIENCE, VOL 5, NO 6 5 6 697 - + 2006年 [査読有り][通常論文]
     
    In this report, the stripe pattern formation of oligonucleotide in Langmuir-Blodgett (LB) monolayer was investigated. A polyion complex monolayer of oligonucleotide and cationic amphiphile spread on a TE buffer solution of a RhodamineX-labeled oligonucleotide was transferred on a glass substrate by the LB method. Fluorescence images of the transferred polyion complex monolayers showed that stripe patterns of the oligonucleotide were formed. The interval of the lines was dependent on the transferring speed of the substrate.
  • K Ijiro, Y Matsuo, Y Hashimoto
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 445 207 - 211 2006年 [査読有り][通常論文]
     
    The precise metallization of double-stranded DNA by the selective electroless plating method was investigated for the purpose of the fabrication of nanowires. Cis-platin was bound to template DNA molecules and reduced to platinum which can catalyze following silver metal deposition. The DNA molecules combined with the platinum clusters was stretched and immobilized on a glass substrate by using the LB method. The electroless plating of the platinum-bound DNA molecules immobilized on the substrate by reduction of silver ion gave uniform silver nanowires (ca. 30 nm height and 50 similar to 100 nm width) along the stretched DNA structures. On the contrary, the electroless plating of DNA molecules without the catalyst provided inhomogeneous silver deposition. Conductive AFM measurement revealed that the obtained silver nanowires as long as several mu m had high conductivities.
  • IJIRO Kuniharu, MATSUO Yasutaka, HASHIMOTO Yuichi
    Mol Cryst Liq Cryst 445 497-501  2006年 [査読無し][通常論文]
  • H Yabu, T Higuchi, K Ijiro, M Shimomura
    CHAOS 15 4 047505  2005年12月 [査読有り][通常論文]
     
    In recent years, polymer nanoparticles have been investigated with great interest due to their potential applications in the fields of electronics, photonics, and biotechnology. Here, we report the spontaneous formation of polymer nanoparticles from a clear solution containing a nonvolatile poor solvent by slow evaporation of a volatile good solvent. During evaporation of the good solvent, the solution gradually turns turbid. After evaporation, polymer nanoparticles of homogeneous shape and size are dispersed in the poor solvent. Homogeneous nucleation and successive growth of polymer particles takes place during the dynamic nonequilibrium process of solvent evaporation. The size of the particles, ranging from tens of nanometers to micrometer scale, depends on both polymer concentration and the solvent mixing ratio. Because of the physical generality of the particle formation mechanism, this procedure is applicable to a wide variety of polymers with suitable combinations of solvents. Here, we also show unique features, surface structures and surface properties of polymer nanoparticles prepared by this method. (C) 2005 American Institute of Physics.
  • Fabrication of Silver Nanowires based on DNA stretched by the LB Method
    Y. Hashimoto, Y. Matsuo, K. Ijiro
    Transactions of the Materials Research Society of Japan 30 671 - 674 2005年09月 [査読有り][通常論文]
  • Kuniharu Ijiro, Yasutaka Matsuo, Yuichi Hashimoto
    e-Journal of Surface Science and Nanotechnology 3 82 - 85 2005年03月03日 [査読有り][通常論文]
     
    For the purpose of the fabrication of nanowires, the metallization of double-stranded DNA by the selective electroless plating method was investigated. Cis-platin was bound to template DNA molecules and reduced to platinum which can catalyze subsequent silver metal deposition. We have found that when DNA-amphiphile polyion complex monolayer, which was formed at the air-water interface, was transferred to a glass substrate by using the Langmuir-Blodgett (LB) method, DNA molecules could be immobilized and stretched on the glass substrate. The DNA molecules combined with the platinum clusters was also stretched and immobilized on a glass substrate by using the LB method. The electroless plating of the platinum-bound DNA molecules immobilized on the substrate by reduction of silver ion gave uniform silver nanowires (c.a. 50nm in width and height) along the stretched DNA structures. On the contrary, the electroless plating of DNA molecules without the catalyst provided inhomogeneous silver deposition. © 2005 The Surface Science Society of Japan.
  • Y Matsuo, K Ijiro, M Shimomura
    COLLOIDS AND SURFACES B-BIOINTERFACES 40 3-4 123 - 126 2005年02月 [査読有り][通常論文]
     
    We have proposed a new technique for stretching single double-stranded DNA molecules on solid substrates by the Langmuir-Blodgett (LB) method. The polyion complex monolayer of a cationic amphiphile and DNA molecules formed at the air-water interface was transferred on a clean glass substrate. Vertical lifting up of the glass substrate provided the transferred monolayer consisting the stretched individual DNA molecules aligned parallel to the lifting direction on the glass. The DNA molecules complexed with the restriction endonuclease (EcoRI) were employed for stretching by using this method. Fluorescence images of the transferred monolayer showed that the EcoRI-binding DNA molecules could be stretched and immobilized on the glass substrate. A specific sequence of DNA recognized by EcoRI was detected as spatial positions of the stretched DNA molecules. (c) 2004 Elsevier B.V. All rights reserved.
  • Y Hashimoto, Y Matsuo, K Ijiro
    CHEMISTRY LETTERS 34 1 112 - 113 2005年01月 [査読有り][通常論文]
     
    Precise and uniform metallization of double-stranded DNA by the selective electroless plating method was investigated for the fabrication of nanowires. Cis-platin was bound to template DNA molecules and reduced to platinum which then catalyzed silver metal deposition. The DNA molecules combined with the platinum clusters were stretched and immobilized on a glass substrate using the Langmuir-Blodgett (LB) method. The electroless plating of the platinum-bound DNA molecules by the reduction of silver ions yielded uniform silver nanowires (ca. 50nm in width and height) along the stretched DNA molecules. Conductive AFM measurements revealed that a high electric conductivity over a length of 6mum from the edge of a micro electrode.
  • Monma F, Tsuruma A, Matsuo Y, Hotta J.-I, Tanaka M, Yamamoto S, Sasaki K, Ijiro K, Nakamura H, Shimomura M
    Polymer Preprints, Japan 54 1 2233  2005年 [査読有り][通常論文]
  • Yamamoto S, Sunami H, Tanaka M, Matsuo Y, Ijiro K, Yamashita S, Morita Y, Shimomura M
    Polymer Preprints, Japan 54 1 887  2005年 [査読有り][通常論文]
  • 居城 邦治
    表面科学 25 3 124 - 130 The Surface Science Society of Japan 2004年03月10日 
    The phenomenon of molecular recognition including further function is common in nature. Host-guest complexation occurring at Langmuir monolayers has been investigated in detail similarly to molecular recognition in solutions. Langmuir monolayers at the air-water interface provide a unique environment for molecular recognition. Characteristic binding efficiency and selectivity of water-soluble substrates by specific pairing of hydrogen bonding have been found for functionalized monolayers at the air-water interface. Hydrogen bonding network formation between a functionalized monolayer and a substrate enables cleavage of the head group of an amphiphile forming the monolayer by hydrolysis of a C=C double bond that links the head group to the hydrophobic tail. Molecular organization termed "molecular recognition-directed self-assembly" has been demonstrated through complementary base-pairing in monolayers at the air-water interface. Controlling of molecular arrangement of nucleobase amphiphiles in Langmuir monolayers has been attempted by using complementary base-pairing with sequence-designed oligonucleotides as a molecular template. This unique molecular recognition should be useful for nanotechnology.
  • H Yabu, M Tanaka, K Ijiro, M Shimomura
    LANGMUIR 19 15 6297 - 6300 2003年07月 [査読有り][通常論文]
     
    Microporous polymer films are attractive materials with potential application in the fields of electronics, photonics, and biotechnology. Chemical and thermal stabilities of the microporous polymer films are required for their materials application. Besides preparation by conventional photolithography, we have reported that honeycomb-patterned porous polymer films are prepared by a method utilizing the condensation of small water droplets on solutions of amphiphilic copolymers. Here, we show preparation of honeycomb-patterned microporous films of a thermally and chemically stable material, polyimide. A water-template-assisted honeycomb structure was formed from a polyion complex of polyamic acids and dialkylammonium salt. The pore size of films was controlled by the casting volume of polymer solution. The patterned polyion complex film converted into polyimide by simple chemical treatment, keeping the porous structure. Self-supporting microporous polyimide films are fabricated. The honeycomb-structured film has high thermal and chemical stability like that of conventional cast films of polyimides.
  • M Shimomura, R Mitamura, J Matsumoto, K Ijiro
    SYNTHETIC METALS 133 473 - 475 2003年03月 [査読有り][通常論文]
     
    Two experimental methods for materialization of DNA as novel molecular devices are described. Two types of Langmuir monolayers complexed with DNA molecules at the air-water interface were prepared for single-DNA stretching and template polymerization of the DNA-mimetics, respectively. Single-DNA molecule can be stretched on the solid surface when the ionic complex of a double-stranded DNA and a cationic monolayer was transferred slowly from water surface to the hydrophilic solid surface by using conventional Langmuir-Blodgett technique. The surface monolayer of the diacetylene containing nucleobase amphiphiles prepared as DNA-mimetics can form complementary hydrogen bonds with single-stranded DNAs at the air-water interface. The single-stranded DNA molecule can act as a template of photopolymerization of the diacetylene groups in the DNA-mimetics. Combination of two methods will provide a new preparation strategy of single molecular devices based on DNA. (C) 2002 Elsevier Science B.V. All rights reserved.
  • K. Ijiro, Y. Matsuo, M. Shimomura
    Nucleic Acids Research Supplement 3 47 - 48 2003年 [査読有り][通常論文]
  • Y Matsuo, K Ijiro, M Shimomura
    ASIANANO 2002, PROCEEDINGS 321 - 325 2003年 [査読有り][通常論文]
     
    We propose a new method that double-stranded DNA molecules can be stretched and immobilized on the clean glass substrate by using a lipid monolayer at the air-water interface. This method is based on the substrate lifting of Langmuir-Blodgett method. We observed fluorescence images of polyion complex films with a scanning near-field optical microscope (SNOM). As a result, straight fluorescent lines aligned parallel to the lifting direction were observed and it was considered that isolated single DNA molecules were extended to align on the substrate. This method is applied to various DNA molecules.
  • Y Hashimoto, K Ijiro, T Sawadaishi, M Shimomura
    ASIANANO 2002, PROCEEDINGS 333 - 337 2003年 [査読有り][通常論文]
     
    We investigated electric conductivities of poly nucleic acid-amphiphile polyion complex monolayers. The polyion complex monolayers were prepared by spreading of dialkylammonium salt on aqueous solutions of various poly nucleic acids. The complex monolayers were compressed at the air-water interface and transferred on comb-shaped Au-electrode substrates by vertical lifting method. I-T plots of the complex monolayers, which were measured under applying direct voltage, suggested that the complex monolayers were dielectric substances. The I-V plots indicated that the conductivity of the monolayer depended on the species of poly nucleic acids. Based on the ac impedance analysis of those monolayers, the bulk resistance of those monolayers was estimated from the complex impedance plane plots.
  • H Sunami, K Ijiro, M Shimomura
    ASIANANO 2002, PROCEEDINGS 293 - 297 2003年 [査読有り][通常論文]
     
    In order to develop a new DNA sequencing method by using chemical force microscopy (CFM), we have investigated the interaction of the hydrogen bonding between surfaces of nucleobase self-assembled monolayers (SAMs) and AFM-tips modified with the nucleobases. The two different adhesion forces, the jump-in force and pull-off force, between the AFM-tip modified with cytosine-SAM and the surfaces of four kinds of nucleobase SAMs were measured in water (20 degrees C) by CFM. The adsorption of poly (C) onto a nucleobase-SAM on a gold electrode of quartz crystal microbalance (QCM) was measured as resonance frequency changes. The relative relation among four bases showed similar tendency in the adhesion force measured by the cytosine AFM-tip and in the adsorption amount of poly (C) on the QCM electrode as well as in the theoretically calculated interaction energies between two nucleobases.
  • K Ijiro, J Matsumoto, M Morisue, M Shimomura
    ASIANANO 2002, PROCEEDINGS 223 - 227 2003年 [査読有り][通常論文]
     
    Monolayers of thymine amphiphile containing azobenzene chromophore (Azo-Thy) were prepared on various aqueous oligonucleotide (dA(30), d(GA)(15), d(GGA)(10)) subphases. Pressure-area isotherms and reflection absorption spectra of the monolayers on dA30 or d(CA)(15) solution showed that the H-aggregate of the azobenzene units was formed at higher surface pressure than 25 mN/m. In contrast, the monolayer on an aqueous d(GGA)(10) solution did not form any aggregates of the azobenzene units even at high surface pressure. Base-pair formation between Azo-Thy and template d(GGA)(10) could give free volume to the azobenzene units in the monolayer to prevent the aggregation of the azobenzene units at the air-water interface.
  • J Nishida, J Matsumoto, M Morisue, K Ijiro, M Shimomura
    ASIANANO 2002, PROCEEDINGS 303 - 307 2003年 [査読有り][通常論文]
     
    In order to construct chromophores arrays that precisely controlled their arrangement, monolayers of an azobenzene bearing nucleoamphiphile were prepared on various oligoDNA solutions. Monolayers of the amphiphilic adenine derivative bearing an azobenezene moiety (C(12)AzoC(5)Ade) were prepared on thymidylic acid tetramer (dT4) and octamer (dT8) solutions, and UV-vis reflection absorption spectra of the monolayers were measured to investigate aggregation structures of the azobenzene. The absorption maximum of the monolayer was blue-shifted on the dT4 solution and red-shifted on the dT8 solution. It shows that azobenzene groups in the monolayer have parallel orientation (H aggregate) on the dT4 solution. Though, azobenzene groups have head-to-tail orientation (J aggregates) on the dT8 solution. When monolayers Of C(12)AzoC(5)Ade were prepared on the synthesized cyclic oligonucleotides, the absorption spectra were totally different from those of the corresponding linear oligonucleotides.
  • K. Ijiro, Y. Matsuo, M. Shimomura
    Interface 2003 79 - 82 2003年 [査読有り][通常論文]
  • Immobilization of Single DNA Molecules Complexed with Cationic Lipid Monolayers towards Novel Molecular Devices
    K. Ijiro, R. Mitamura, J. Matsumoto, K. Kago, R. Yoshitome, H. Matsuoka, H. Yamaoka, M. Shimomura
    Nanotechnology toward the Organic Photonics 351 - 358 2002年05月 [査読無し][通常論文]
  • K Ijiro, H Sunami, K Arai, J Matsumoto, O Karthaus, S Kraemer, S Mittler, N Nishi, B Juskowiak, S Takenaka, W Knoll, M Shimomura
    COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS 198 677 - 682 2002年02月 [査読有り][通常論文]
     
    Self-assembled monolayers (SAMs) of double-chain disulfide derivatives of nucleobases (adenine and thymine) were formed on Au substrates in order to measure complementary hydrogen bonding by chemical force microscopy at the interfaces. Surface plasmon resonance measurements indicated that the formation of the nucleobase SAMs on Au surface was completed within 80 min. To measure adhesion force by atomic force microscopy (AFM), Au-coated AFM tips were modified with the nucleobase SAMs, too. SAM-modified An substrates micro-patterned on quartz substrates were prepared for adhesion force mapping. The adhesion force between the complementary nucleobases is larger than that of the non-complementary combination. Electrochemical detection using a redox-intercalator was demonstrated for hybridization of single-stranded polynucleic acid with the nucleobase SAMs modified on Au electrodes. (C) 2002 Elsevier Science B.V. All rights reserved.
  • J Nishida, KA Nishikawa, S Nishimura, S Wada, T Karino, T Nishikawa, K Ijiro, M Shimomura
    POLYMER JOURNAL 34 3 166 - 174 2002年 [査読有り][通常論文]
     
    This article describes novel three methods for micro-patterning of cell adhesive ligands by using the self-organized honeycomb-patterned structure formed by the simple cast method. A first method is a direct preparation of a patterned film by casting an amphiphilic polymer containing lactose residue which is one of cell adhesive ligands. A benzene solution of the amphiphilic polymer was cast at high humidity on a glass substrate. Atomic force microscopy (AFM) observation of the film showed that a honeycomb pattern with microporousness with as large as micrometer size in diameter was formed. The film was immersed into an aqueous fluorescence-labeled lectin solution to investigate the distribution of lactoses on the patterned film. Consistence of a fluorescence image of the lectin bound film with the honeycomb pattern showed that the lactose residues were existed not at the holes but at the rims of the honeycomb-patterned film. A second method is to immobilize gelatin, which is one also one of cell adhesive ligands, on the honeycomb-patterned film by chemical reaction. A honeycomb-patterned film was prepared from chloroform solution of an amphiphilic polymer containing reactive succinimide ester groups, and then the film was immersed into an aqueous fluorescence-labeled gelatin solution to introduce gelatin on the film surface. Immobilization of gelatin onto honeycomb-patterned film was confirmed by the fluorescence microscope. A third method is another way to introduce gelatin onto the honeycomb film by the specific avidin-biotin interaction. A honeycomb-patterned film was prepared from amphiphilic polymer containing biotin residues and dodecyl groups, and then the film was immersed into a avidin solution and a biotinylated fluorescence labeled gelatin solution successively. By the fluorescence microscopic observation of the film, gelatin was confirmed to be immobilized at the rims of the honeycomb pattern via the avidin-biotin interaction. Cell culture was performed on the gelatin immobilized patterned film prepared by second method. Bioactivity of gelatin immobilized honeycomb-patterned film was confirmed by adhesion of cell onto the film.
  • Yuichi Hashimoto, Kuniharu Ijiro, Tetsuro Sawadaishi, Masatsugu Shimomura
    International Journal of Nanoscience, Vol 1, Nos 5 and 6 1 5-6 707 - 711 2002年 [査読有り][通常論文]
     
    We investigated electric conductivities of poly nucleic acid-amphiphile polyion complex monolayers. The polyion complex monolayers were prepared by spreading of dialkylammonium salt on aqueous solutions of various poly nucleic acids. The complex monolayers were compressed at the air-water interface and transferred on comb-shaped Au-electrode substrates by vertical lifting method. I-T plots of the complex monolayers, which were measured under applying direct voltage, suggested that the complex monolayers were dielectric substances. The I-V plots indicated that the conductivity of the monolayer depended on the species of poly nucleic acids. Based on the ac impedance analysis of those monolayers, the bulk resistance of those monolayers was estimated from the complex impedance plane plots.
  • Kuniharu Ijiro, Jin Matsumoto, Mitsuhiko Morisue, Masatsugu Shimomura
    International Journal of Nanoscience, Vol 1, Nos 5 and 6 1 5-6 597 - 601 2002年 [査読有り][通常論文]
     
    Monolayers of thymine amphiphile containing azobenzene chromophore (Azo-Thy) were prepared on various aqueous oligonucleotide (dA(30), d(GA)(15), d(GGA)(10)) subphases. Pressure-area isotherms and reflection absorption spectra of the monolayers on dA(30) or d(GA)(15) solution showed that the H-aggregate of the azobenzene units was formed at higher surface pressure than 25 mN/m. In contrast, the monolayer on an aqueous d(GGA)(10) solution did not form any aggregates of the azobenzene units even at high surface pressure. Base-pair formation between Azo-Thy and template d(CGA)(10) could give free volume to the azobenzene units in the monolayer to prevent the aggregation of the azobenzene units at the air-water interface.
  • Jin Nishida, Jin Matsumoto, Mitsuhiko Morisue, Kuniharu Ijiro, Masatsugu Shimomura
    International Journal of Nanoscience, Vol 1, Nos 5 and 6 1 5-6 677 - 681 2002年 [査読有り][通常論文]
     
    In order to construct chromophores arrays that precisely controlled their arrangement, monolayers of an azobenzene bearing nucleoamphiphile were prepared on various oligoDNA solutions. Monolayers of the amphiphilic adenine derivative bearing an azobenezene moiety (C(12)AzoC(5)Ade) were prepared on thymidylic acid tetramer (dT4) and octamer (dT8) solutions, and UV-vis reflection absorption spectra of the monolayers were measured to investigate aggregation structures of the azobenzene. The absorption maximum of the monolayer was blue-shifted on the dT4 solution and red-shifted on the dT8 solution. It shows that azobenzene groups in the monolayer have parallel orientation (H aggregate) on the dT4 solution. Though, azobenzene groups-have head-to-tail orientation (J aggregates) on the dT8 solution. When monolayers of C(12)AzOC(5)Ade were prepared on the synthesized cyclic oligonucleotides, the absorption spectra were totally different from those of the corresponding linear oligonucleotides.
  • Molecular Recognition of Nucleobeses Attached to Self-Assembled Monolayers Detected by Chemical Rrce Microscopy and Quartz Crystal
    H. Sunami, K. Ijiro, M. Shimomura
    International Journal of Nanoscience 1 5-6 667 - 671 2002年 [査読有り][通常論文]
  • Yasutaka Matsuo, Kuniharu Ijiro, Masatsugu Shimomura
    International Journal of Nanoscience, Vol 1, Nos 5 and 6 1 5-6 695 - 699 2002年 [査読有り][通常論文]
     
    We propose a new method that double-stranded DNA molecules can be stretched and immobilized on the clean glass substrate by using a lipid monolayer at the air-water interface. This method is based on the substrate lifting of Langmuir-Blodgett method. We observed fluorescence images of polyion complex films with a scanning near-field optical microscope (SNOM). As a result, straight fluorescent lines aligned parallel to the lifting direction were observed and it was considered that isolated single DNA molecules were extended to align on the substrate. This method is applied to various DNA molecules.
  • 橋本 裕一, 澤田石 哲郎, 居城 邦治, 下村 政嗣
    高分子論文集 59 10 651 - 655 2002年 [査読無し][通常論文]
     
    A patterned film of a conducting polymer, poly(3-hexylthiophene) (PHT) was prepared by a simple casting method on its microstructured Au-electrode. Line structures (1.5 ∼ 3 μm wide, 70 nm height) lie in a uniform array at regular intervals in this film. Electronic conductivity between a conducting cantilever and the micro-structured electrode on the substrate through one thin line of PHT was measured by conducting atomic force microscopy (conducting AFM). Topographic image and current mapping showed that the current flowed through only the PHT line. Large current was observed at the boundary surface of the micro electrode. Electric current decreased in proportion to the distance between the cantilever and the micro electrode over 500 nm. This indicates that ohmic conductivity was dominant in the thin line of PHT. When the conventional conducting AFM was modified with an optical filter, photo conductivity could be measured by irradiation of laser light to excite the polymer thin line. Irradiation of the light (λ=488 nm) increased the electric current through the thin line of PHT. The electric conductivity of the line structure in the patterned film of PHT was higher than that of the uniform cast film due to higher molecular organization of PHT in the thin line structure.
  • Hiroshi Sunami, Kuniharu Ijiro, Masatsugu Shimomura
    International Journal of Nanoscience, Vol 1, Nos 5 and 6 1 5-6 667 - 671 2002年 [査読有り][通常論文]
     
    In order to develop a new DNA sequencing method by using chemical force microscopy (CFM), we have investigated the interaction of the hydrogen bonding between surfaces of nucleobase self-assembled monolayers (SAMs) and AFM-tips modified with the nucleobases. The two different adhesion forces, the jump-in force and pull-off force, between the AFM-tip modified with cytosine-SAM and the surfaces of four kinds of nucleobase SAMs were measured in water (20 degrees C) by CFM. The adsorption of poly (C) onto a nucleobase-SAM on a gold electrode of quartz crystal microbalance (QCM) was measured as resonance frequency changes. The relative relation among four bases showed similar tendency in the adhesion force measured by the cytosine AFM-tip and in the adsorption amount of poly (C) on the QCM electrode as well as in the theoretically calculated interaction energies between two nucleobases.
  • Y Hashimoto, T Sawadaishi, K Ijiro, M Shimomura
    KOBUNSHI RONBUNSHU 59 10 651 - 655 2002年 [査読有り][通常論文]
     
    A patterned film of a conducting polymer, poly(3-hexylthiophene) (PHT) was prepared by a simple casting method on its microstructured Au-electrode. Line structures (1.5 similar to 3 mum wide, 70 nm height) lie in a uniform array at regular intervals in this film. Electronic conductivity between a conducting cantilever and the micro-structured electrode on the substrate through one thin line of PHT was measured by conducting atomic force microscopy (conducting AFM). Topographic image and current mapping showed that the current flowed through only the PHT line. Large current was observed at the boundary surface of the micro electrode. Electric current decreased in proportion to the distance between the cantilever and the micro electrode over 500 nm. This indicates that ohmic conductivity was dominant in the thin line of PHT. When the conventional conducting AFM was modified with an optical filter, photo conductivity could be measured by irradiation of laser light to excite the polymer thin line. Irradiation of the light (lambda =488 nm) increased the electric current through the thin line of PHT. The electric conductivity of the line structure in the patterned film of PHT was higher than that of the uniform cast film due to higher molecular organization of PHT in the thin line structure.
  • S Ikeda, H Nur, T Sawadaishi, K Ijiro, M Shimomura, B Ohtani
    LANGMUIR 17 26 7976 - 7979 2001年12月 [査読有り][通常論文]
     
    Amphiphilic NaY zeolite particles were prepared by a partial modification of the external surface of NaY with alkylsilyl groups. When the particles were added to a mixture of aqueous hydrogen peroxide and normal alkene, they were feasibly located just at the liquid-liquid phase boundary and efficiently catalyzed epoxidation of the alkenes even without stirring. Fluorescence microscopic observation of these particles selectively modified with fluorescent dye revealed that each particle has a bimodal amphiphilic surface structure; one side of the external surface is hydrophilic and the other is hydrophobic.
  • S Ikeda, H Nur, T Sawadaishi, K Ijiro, M Shimomura, B Ohtani
    LANGMUIR 17 26 7976 - 7979 2001年12月 [査読無し][通常論文]
     
    Amphiphilic NaY zeolite particles were prepared by a partial modification of the external surface of NaY with alkylsilyl groups. When the particles were added to a mixture of aqueous hydrogen peroxide and normal alkene, they were feasibly located just at the liquid-liquid phase boundary and efficiently catalyzed epoxidation of the alkenes even without stirring. Fluorescence microscopic observation of these particles selectively modified with fluorescent dye revealed that each particle has a bimodal amphiphilic surface structure; one side of the external surface is hydrophilic and the other is hydrophobic.
  • T Mori, S Kishimoto, K Ijiro, A Kobayashi, Y Okahata
    BIOTECHNOLOGY AND BIOENGINEERING 76 2 157 - 163 2001年09月 [査読有り][通常論文]
     
    A lipid-coated lipase has been known to be soluble in organic solvents and act as an efficient esterification catalyst in the dry organic solvent. It was also found to act as an efficient hydrolytic catalyst for lipophilic esters in the two-phase aqueous-organic system. Both the lipid-coated lipase and substrates are solubilized in the organic phase and the hydrolysis occurs with water molecules from the aqueous phase. Therefore, the reaction was 40-100 times faster than that of the native lipase, in which the enzyme and substrate exist separately in the aqueous and organic phase, respectively, and the reaction proceeded at the interface. The hydrolysis rates for the lipid-coated lipase were not affected by the aqueous pH and agitation speed of the two-phase. Enzymatic activity of the lipid-coated lipase was compared with that of the poly(ethylene glycol)-grafted lipase. Michaelis-Menten kinetics in the two-phase reactions was also studied. (C) 2001 John Wiley & Sons, Inc.
  • Molecular Assemblies Based on DNA-Mimetics: Effect of Monolayer Matrix on Photopolymerization of Diacetylene-containing Nucleobase monolayers
    Kuniharu Ijiro, Jin Matsumoto, Masatsugu Shimomura
    Studies in Surface Science and Catalysis 132 481 - 484 2001年02月 [査読有り][通常論文]
  • J Matsumoto, K Ijiro, M Shimomura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 371 33 - 36 2001年 [査読有り][通常論文]
     
    Pressure-area isotherms of ternary component monolayers of nucleobase amphiphiles, octadecylcytosine (C-18-Cyt) and diacetylene-containing adenine and thymine amphiphiles (DA-Ade, DA-Thy), were changed by addition of oligonucleotides, d(GT)(15) or d(GGT)(10), in the water subphase. Photopolymerization of diacetylene in the monolayer was strongly suppressed on the oligonucleotide subphase. This suggests that the oligonucleotide can act as a template for the diacetylene monomer arrangement via complementary hydrogen bonding at the air-water interface.
  • K Ijiro, T Sawadaishi, M Shimomura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 371 375 - 378 2001年 [査読無し][通常論文]
     
    Regularly arrayed mesoscopic lines of DNA, parallel to the receding direction of the solvent, can be prepared by simple casting from an aqueous solution. Photocurrent of single fine of DNA assemblies containing intercalators, acridine orange, was generated when the patterned cast film was irradiated by the light at 480nm, through the excitation of the intercalators.
  • MORISUE M, IJIRO K, SHIMOMURA M
    Mol. Cryst. Liq. Crys. 371 379 - 382 2001年 [査読無し][通常論文]
  • T Sawadaishi, K Ijiro, M Shimomura, Y Shiraishi, N Toshima, T Yonezawa, T Kunitake
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 371 123 - 126 2001年 [査読無し][通常論文]
     
    Two-dimensional regular patterns of nanoparticles were formed on solid substrate by casting colloidal dispersion. Periodic stripes were formed on mica surface parallel to the receding direction of casting solution. The thickness of each stripe was estimated to be comparable to that of monolayer of particles. From atomic force microscopy (AFM) and scanning electron microscopy (SEM), it was cleared that the monolayer of silica particles were hexagonally packed.
  • Hiroshi Sunami, Kuniharu Ijiro, Olaf Karthaus, Stephan Kraemer, Silvia Mittler, Wolfgang Knoll, Masatsugu Simomura
    Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals 371 151 - 154 2001年 [査読無し][通常論文]
     
    In order to measure complementary hydrogen bonding between nucleobases, disulfide derivatives of thymine and adenine were newly synthesized. Surface Plasmon Resonance SPR confirmed the formation of SAMs on Au. SPR shows that SAMs of nucleobase derivatives were completely formed within 60 minutes. Thickness of the adenine SAM and the thymine SAM is nearly the same. AFM tip was modified with the thymine SAM. The adenine SAM-modified Au electrode was clearly observed in an adhesion force map. The adhesion force between complementary nucleobases is larger than that of the non-complementary combination. © 2001 Tayor and Francis, Inc.
  • 二次元DNA-mimeticsの鋳型光重合
    松本仁, 居城邦治, 下村政嗣
    光化学 32 1 - 6 2001年 [査読有り][通常論文]
  • H Sunami, K Ijiro, O Karthaus, S Kraemer, S Mittler, W Knoll, M Simomura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 371 151 - 154 2001年 [査読有り][通常論文]
     
    In order to measure complementary hydrogen bonding between nucleobases, disulfide derivatives of thymine and adenine were newly synthesized. Surface Plasmon Resonance; SPR confirmed the formation of SAMs on Au. SPR shows that SAMs of nucleobase derivatives were completely formed within 60 minutes. Thickness of the adenine SAM and the thymine SAM is nearly the same. AFM tip was modified with the thymine SAM. The adenine SAM-modified Au electrode was clearly observed in an adhesion force map. The adhesion force between complementary nucleobases is larger than that of the non-complementary combination.
  • J Matsumoto, K Ijiro, M Shimomura
    CHEMISTRY LETTERS 11 1280 - 1281 2000年11月 [査読無し][通常論文]
     
    An amphiphilic diacetylene with thymine (DA-Thy) was newly synthesized. The amphiphile can form solid-state monolayer and photopolymerize with UV light irradiation at the air-water interface to form blue and red forms of polydiacetylene. Shapes of the crystalline domain of the polydiacetylene monolayer were changed by base pair formation between DA-Thy and adenine nucleobase dissolved in the water subphase.
  • 居城 邦治
    高分子 49 11 781 - 781 公益社団法人 高分子学会 2000年11月01日
  • M Weisser, J Kashammer, B Menges, J Matsumoto, F Nakamura, K Ijiro, M Shimomura, S Mittler
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 122 1 87 - 95 2000年01月 [査読無し][通常論文]
     
    The formation of the base pair adenine-uracil at a water- solid interface, at an immobilized monolayer of adenine disulfide with adenine groups exposed to the very surface, respectively, is shown here. To overcome the steric hindrance of tightly packed adenine groups in a pure adenine thiolate monolayer on gold, the formation of self-assembled monolayers out of a binary mixture of the adenine disulfide and CH3- or OH-terminated thiols are investigated. Electro-chemical investigations, surface plasmon spectroscopy (PSP, plasmon surface polariton), multimode waveguide-PSP-coupling spectroscopy, contact angle measurements, and spontaneous desorption time-of-flight mass spectrometry were used to characterize the monolayers. The specific base pairing was investigated for a variety of monolayer compositions. A specific base pairing was successful for an optimized mixed adenine/OH-terminated thiol monolayer. Nevertheless unspecific binding is a problem.
  • K Kago, H Matsuoka, R Yoshitome, H Yamaoka, K Ijiro, M Shimomura
    LANGMUIR 15 16 5193 - 5196 1999年08月 [査読無し][通常論文]
     
    Direct in situ observation of the fine structure of the cationic lipid monolayer-DNA complex on a water surface has been carried out. by using an air-water interface X-ray reflectivity (XR) instrument. Interestingly, the thickness of the DNA layer was markedly thinner than the geometry of the cylindrical DNA molecule when the complex was deposited on the solid substrates; the thickness was determined to be 11 Angstrom by XR measurement in a dried state, while the diameter of the DNA molecule is about 24 Angstrom. However, the thickness in the complex on a water surface was estimated by in situ XR measurement to be about 25-28 Angstrom, which is comparable to the geometry of the DNA molecule. Thus, the anomalously thin thickness was due to some experimental treatments, such as deposition on a solid substrate and/or drying. The structure of the monolayer and monolayer-polymer complex on the solid substrates in a dried state is not the same as that on a water surface. The possibility of some dynamic fluctuation of its structure was also suggested. These results strongly indicate the importance of a direct in situ study such as by the XR technique for the structural study of the monolayer and monolayer complex on a water surface.
  • K Ijiro, T Ikeda, M Shimomura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 327 45 - 48 1999年 [査読無し][通常論文]
     
    Fluorescence quenching of an amphiphilic intercalator (an electron donor, C(18)AO(+)) by an amphiphilic viologen (an electron acceptor, C(12)BhpC(5)V(2+)) in a cationic monolayer of 2C(18)N(+)2C(1) was enhanced when the monolayer formed polyion complexes with double-stranded polynucleotides at the air-water interface. Fluorescence intensity and quenching efficiency were strongly depended on structure of polynucleotides.
  • M Morisue, H Nakamura, K Ijiro, M Shimomura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 337 457 - + 1999年 [査読無し][通常論文]
     
    An amphiphilic cytosine derivative containing an azobenzene chromophore was prepared in order to align azobenzene chromophores along single-strand DNA as a template. The trans-amphiphile was too coalescent to be spread as a monolayer at the air-water interface. On the other hand, the cis-amphiphile formed an expanded monolayer. After photoisomerization of the cis-monolayer with the visible light irradiation at the air-water interface, the regenerated trans-amphiphile can form a stable monolayer only on the guanosine subphase.
  • M Shimomura, J Matsumoto, F Nakamura, T Ikeda, T Fukasawa, K Hasebe, T Sawadaishi, O Karthaus, K Ijiro
    POLYMER JOURNAL 31 11 1115 - 1120 1999年 [査読無し][通常論文]
     
    Toward the functional application of DNA as novel molecular devices, we have immobilized DNA as two-dimensional molecular assemblies by means of specific intermolecular interaction at the air-water interface. Preparation of DNA-mimetics at the air-water interface is briefly shown in the second part of this paper. The final part describes micropattern formation of DNA assemblies by using a novel lithography-free technique based on a general physical phenomenon. Mesoscopic two-dimensional patterns of DNA assemblies are prepared by freezing of dissipative structures formed in casting processes of DNA solution.
  • N Ohta, M Nakamura, Yamazaki, I
    LANGMUIR 14 21 6226 - 6230 1998年10月 [査読無し][通常論文]
     
    Surface morphology of oxacyanine dye (OC) suddenly changes in mixed Langmuir-Blodgett films composed of OC, arachidic acid, and methyl arachidate when the OC fraction becomes more than 30 mol %. The agglomerates of OC show a ring structure just like a rubber band. The diameter and the shape of the "rubber band" change with different OC fractions, and microcrystalline domains appear when J-type aggregates are formed. The morphological change of the surface monolayer is well-correlated with a change in the electroabsorption spectra of the OC chromophore.
  • F Nakamura, K Ijiro, M Shimomura
    THIN SOLID FILMS 327 603 - 606 1998年08月 [査読無し][通常論文]
     
    In order to construct mio dimensional DNA-mimetics, nucleo base monolayers, composed of amphiphilic adenine and thymine derivatives, were prepared at the air-water interface. The monolayer were characterized by pressure-area isotherm measurements, UV-Vis absorption and FT-IR reflection-absorption spectroscopy (RAS), and fluorescence spectroscopy and microscopy. A 1:1 mixture of octadecyladenine (C-18-Ade) and octadecylthymine (C-18-Thy) formed the most condensed monolayer on a pure water subphase in the three combinations of the equimolar mixtures of C-18-Ade, C-18-Thy, and octadecylcytosine (C-18-Cyt). A FT-IR RAS spectrum of the transferred monolayer suggests the base-pairing with Watson-Crick type hydrogen bonds in the C-18-Ade/C-18-Thy monolayer. An in situ observation of fluorescence image and spectrum at the air-water interface indicates that the Watson-Crick type monolayer can incorporate an amphiphilic intercalator, octadecylacridineorange (C-18-AO), as well as DNA. (C) 1998 Elsevier Science S.A. All rights reserved.
  • N Maruyama, T Koito, J Nishida, T Sawadaishi, Cieren, X, K Ijiro, O Karthaus, M Shimomura
    THIN SOLID FILMS 327 854 - 856 1998年08月 [査読無し][通常論文]
     
    A two-dimensional micron-sized honeycomb structure was formed when a chloroform solution of an amphiphilic polymer was cast on solid surfaces at high atmospheric humidity. This simple method is widely applicable for patterning of molecular aggregates on solid surfaces. Mesoscopic patterns are demonstrated to be formed spontaneously from a variety of amphiphilic polyion complexes, amphiphilic covalent polymers, and organic-inorganic hybrid materials. Size and structure of the patterns can be regulated by concentration, atmospheric humidity, etc. (C) 1998 Elsevier Science S.A. All rights reserved.
  • N Maruyama, O Karthaus, K Ijiro, M Shimomura, T Koito, S Nishimura, T Sawadaishi, N Nishi, S Tokura
    SUPRAMOLECULAR SCIENCE 5 3-4 331 - 336 1998年07月 [査読無し][通常論文]
     
    Hierarchical mesoscopic structures of the nanoscopic supramolecular assemblies, which consist of polyelectrolytes and bilayer-forming amphiphiles, are prepared by a simple and new solvent-casting method. Submicron scale 2-D structures, e.g. regular dots, stripes, and networks, are formed when highly diluted organic solutions of polymer assemblies are cast on solid surfaces. Dynamic mesoscopic regular structures, the so-called 'dissipative structures', formed in the non-equilibrium processes of solvent-casting are fixed as hierarchically structured polymer assemblies. (C) 1998 Elsevier Science Limited. All rights reserved.
  • J Hellmann, M Hamano, O Karthaus, K Ijiro, M Shimomura, M Irie
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 37 7A L816 - L819 1998年07月 [査読無し][通常論文]
     
    Atomic force microscopic (AFM) imaging revealed that a polyether third generation dendrimer having a photochromic dithienylethene core group forms regularly aligned (hexagonal alignment) droplets of more or less equal size (100-120 nm) and height of the long axis of the dendrimer (5.0 +/- 0.5 nm) on a mica surface when the surface is rinsed with a benzene solution of the dendrimer. The size suggests that one droplet contains around 10(4) dendrimers. The subtle balance among surface hydrophilicity, hydrophobicity of solvent and dendrimers, and structure or shape of the dendrimers is considered to control the regular alignment.
  • K Ijiro, H Ringsdorf, E Birch-Hirschfeld, S Hoffmann, U Schilken, M Strube
    LANGMUIR 14 10 2796 - 2800 1998年05月 [査読無し][通常論文]
     
    The specific interaction of streptavidin with biotinylated lipids at the air-water interface leads to a formation of optically anisotropic two-dimensional streptavidin (2-D) crystals, where two of the original four biotin-binding sites remain free. These assembled streptavidin matrixes were used as a template for docking of double-stranded oligonucleotides biotinylated at a terminal or a centered position. A biotinylated lipid monolayer was deposited on an electrode of a quartz crystal microbalance (QCM), and docking processes of the protein and the oligonucleotides were detected as frequency changes related by mass changes on the QCM. The bis-biotinylated double-stranded oligonucleotides bound to the primary streptavidin layers made it possible to engineer protein-DNA-protein triple layers. Hydrolysis by a restriction endonuclease indicates that the biotinylated DNA bound to the streptavidin layers remains bioactive.
  • K Ijiro, F Nakamura, M Shimomura
    MOLECULAR RECOGNITION AND INCLUSION 361 - 364 1998年 [査読無し][通常論文]
  • T Sukegawa, M Matsuda, SI Nishimura, M Shimomura, K Ijiro, O Karthaus
    MOLECULAR RECOGNITION AND INCLUSION 519 - 522 1998年 [査読無し][通常論文]
     
    A novel amphiphilic cyclodextrin derivative having sialic acid residues was systematically synthesised. Hexakis (2,3-di-O-palmitoyl)-di-6-O-toluenesulfonyl-alpha-cyclodextrin cyclodextrin was converted to hexakis (2,3-di-O-palmitoyl)-6-di-(2-aminoethyl)-amino-6-dideoxy-alpha-cyclodextrin by reaction with ethylenediamine as a reactive spacer. Coupling of a sialic acid intermediate and alpha-cyclodextrin derivative gave an amphiphilic cyclodextrin derivative having two sialic acid residues. This unique compound showed an excellent ability to form monolayer membrane.
  • Masatsugu Shimomura, Takeo Koito, Norihiko Maruyama, Keiko Arai, Jin Nishida, Lars Grasjoe, Olaf Karthaus, Kuniharu Ijiro
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 322 305 - 312 1998年 [査読有り][通常論文]
     
    Mesoscopic two-dimensional patterns, regular dots, stripes, and honeycomb networks are formed when dilute organic solutions of polymers are cast on solid surfaces. Dynamic patterns, so-called "dissipative structures", formed in the non-equilibrium thermodynamic process of solvent evaporation, are fixed as the two-dimensional polymer patterns on substrates. Some photonic and electronic applications of the mesoscopic polymer patterns are described in this article.
  • 下村 政嗣, 居城 邦治
    高分子 46 5 334 - 334 公益社団法人 高分子学会 1997年05月
  • M Shimomura, F Nakamura, K Ijiro, H Taketsuna, M Tanaka, H Nakamura, K Hasebe
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 119 9 2341 - 2342 1997年03月 [査読無し][通常論文]
  • Mesoscopic Patterns of DNA-Amphiphile Complexes
    M. Shimomura, O. Karthaus, N. Maruyama, K. Ijiro, T. Sawadaishi, S. Tokura, N. Nishi
    Rep. Prog. Polym. Phys. Jpn. 40 523 - 524 1997年 [査読無し][通常論文]
  • O Karthaus, K Ijiro, M Shimomura, J Hellmann, M Irie
    LANGMUIR 12 26 6714 - 6716 1996年12月 [査読有り][通常論文]
  • M Shimomura, F Nakamura, K Ijiro, H Taketsuna, M Tanaka, H Nakamura, K Hasebe
    THIN SOLID FILMS 284 691 - 693 1996年09月 [査読有り][通常論文]
     
    A stable monolayer assembly of octadecylcytosine, which can not be spread as a monolayer on pure water subphase, was formed when a small amount of guanosine was added to the water subphase. Spiral shaped two-dimensional crystal domains of the monolayer were observed by a fluorescence microscope. Fourier transform IR spectrum of the deposited monolayer prepared on the guanosine subphase strongly suggests complementary base pairing at the interface.
  • K Ijiro, M Shimomura, M Tanaka, H Nakamura, K Hasebe
    THIN SOLID FILMS 284 780 - 783 1996年09月 [査読有り][通常論文]
     
    The interaction of a newly synthesized cationic intercalator amphiphile C(18)AO into double-stranded DNAs at the air-water interface was investigated. Polyion complex monolayers consisting of DNAs and cationic amphiphiles were prepared, Pressure-area isotherms. fluorescence measurements, Fourier transform infrared-reflection-absorption spectroscopy and quartz crystal microbalance measurements suggest that C(18)AO molecules can be intercalated into base-pairs of DNAs to form densely packed two-dimensional DNA arrays at the air-water interface.
  • M Shimomura, O Karthaus, K Ijiro
    SYNTHETIC METALS 81 2-3 251 - 257 1996年08月 [査読有り][通常論文]
     
    A newly proposed 'crystal engineering' based on two-dimensional supramolecular assemblies, e.g. bilayer membranes, is shown to be quite useful for tailoring stacked alpha-electron arrays which are applicable to molecular photonics devices of long-range energy and/or electron transportation. Formation and migration of singlet excitons through pi-electron arrays of stilbene chromophores and tailoring of charge transfer complexes of viologen amphiphiles are described as successful examples of the two-dimensional 'crystal engineering' for constructing stacked pi-electron arrays directing photoinduced electron transfer. Molecular-recognition-directed assembling of nucleic acid-base pairs at the air/water interface is shown to be another method of tailoring stacked pi-electron arrays.
  • O Karthaus, K Ijiro, M Shimomura
    CHEMISTRY LETTERS 9 821 - 822 1996年 [査読有り][通常論文]
     
    The formation of ordered patterns of nanosize polystyrene aggregates was observed by atomic force scopy. The samples were prepared by simply rinsing a mica surface with a dilute polymer solution in benzene.
  • Masatsugu Shimomura, Olaf Karthaus, Kuniharu Ijiro
    Supramolecular Science 3 1-3 61 - 65 1996年 [査読有り][通常論文]
     
    Two-dimensional supramolecular organizates are shown to be powerful tools for constructing oriented π-electron arrays, which are applicable to molecular photonics devices and artificial photosynthesis. Complementary hydrogen bonding at the interface of an amphiphilic nucleobase monolayer can form two-dimensional stacking of base-pairs, which is expected to be an electron medium for photoinduced electron transfer as well as double-strand DNAs. DNAs are also immobilized as a monomolecular film of the polyion-complex with an amphiphilic cationic intercalator. A new type of monolayer-forming stilbene amphiphile having a trinitrofluorenylidene group is prepared for designing spatially separated electron donor and acceptor layers.
  • Y OKAHATA, A HATANO, K IJIRO
    TETRAHEDRON-ASYMMETRY 6 6 1311 - 1322 1995年06月 [査読有り][通常論文]
     
    Lipase OF from Candida showed only low enantioselectivity for esterification of (R)- or S-1-phenylethanol with lauric acid (v(R)/v(S) = 5.5). However, when lipase OF was imprinted with a substrate analogue such as (R)-1-phenylethanol and then coated with synthetic glycolipid molecules, the imprinted lipid-coated lipase shows a large enantioselectivity for the esterification in anhydrous isooctane (v(R)/v(S) = 77). When the native lipase OF was imprinted by the same procedure, the enantioselectivity hardly changed. The lipid coating was important to keep the imprinted structure as well as to solubilize enzymes in organic solvents. The improved enantioselectivity was confirmed from Michaelis-Menten kinetics as due to the intramolecular catalytic reaction and not the; substrate binding process. The improved enantioselectivity reverts to the original non-imprinted value if kept in the organic solvents at high temperatures for days.
  • Y OKAHATA, Y FUJIMOTO, K IJIRO
    JOURNAL OF ORGANIC CHEMISTRY 60 7 2244 - 2250 1995年04月 [査読有り][通常論文]
     
    A lipid-coated lipase was prepared, in which hydrophilic head groups of lipids interact with the hydrophilic surface of the enzyme and lipophilic alkyl chains extend away from its surface and solubilize the enzyme in hydrophobic organic solvents. Enantioselective esterification of(R)- or (S)-1-phenylethanol with aliphatic acid was studied in the presence of the lipid-coated lipase, solubilized homogeneously in organic solvents, by varying lipase origin, coating lipid molecules, reaction media, and substrate structures. The lipid-coated lipase prepared from the glycolipid (1) and lipase B from Pseudomonas fragi 22-39B showed both a high catalytic activity and enantioselectivity for the esterification of (R)-1-phenylethanol with long-chain aliphatic acid in dry isooctane, relative to other enzyme systems such as poly(ethylene glycol)-grafted lipase, lipase powder directly dispersed in organic solvents, and a water/organic emulsion system. The coating lipids are found to not affect the enzyme reactions and to act simply as lipophilic tails in organic media. The lipid-coated lipase is suitable for studying the reaction mechanism of the enzyme in organic solvents since the reaction is carried out in homogeneous media. It has been found in studying Michaelis-Menten kinetics that the lipid-coated lipase (or native lipase) has two binding sites for long-chain aliphatic acids and for enantiomorphic secondary alcohols having a small methyl and a large phenyl side chain. Aliphatic acid is bound first and then alcohol. The enantioselectivity of the esterification is determined by the nucleophilic attack of the enantiomorphic alcohol, but not in the binding process of the enantiomorphic alcohol.
  • Y OKAHATA, K NIIKURA, K IJIRO
    JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 1 7 919 - 925 1995年04月 [査読有り][通常論文]
     
    A lipid-coated phospholipase D (PLD) was prepared by mixing aqueous solutions of PLD and lipids. The lipid-coated PLD showed a high catalytic activity for transphosphatidylation of egg yolk phosphatidylcholine (egg-PC) with alcohols in two-phase benzene-acetate buffer solution. Since both substrates and enzymes are soluble in the organic phase, the reaction proceeded in the benzene phase and the aqueous phase is required to remove the produced choline moiety from the organic phase. When a native PLD was employed instead of the lipid-coated PLD, the reaction was very slow (similar to 1/300 that of the lipid-coated PLD) because the reaction occurs at the interface of the lipophilic substrates and water-soluble enzymes. The transphosphatidylation catalysed by a lipid-coated PLD could be applied in a manner widely independent of the nature of the head groups of the coating lipids and the polarity of the organic solvents, and could be applied also on a large-scale (yield 1-2 g) synthesis to introduce various alcohols, sugars, and nucleic acids at the head groups of phospholipids. We have determined substrate selectivity and Michaelis-Menten kinetics for a lipid-coated PLD and compared the results with those for the native PLD.
  • Y OKAHATA, Y MATSUZAKI, K IJIRO
    SENSORS AND ACTUATORS B-CHEMICAL 13 1-3 380 - 383 1993年05月 [査読有り][通常論文]
     
    A water-insoluble, self-standing cast film of a DNA-lipid complex is prepared by mixing aqueous solutions of both anionic DNAs and cationic amphiphiles at a charge ratio of 1:1. Intercalation behaviours of dye molecules into a cast film of a DNA-lipid complex deposited on a quartz-crystal microbalance (QCM) are followed quantitatively by observing frequency changes of the QCM in an aqueous solution.
  • Y OKAHATA, K IJIRO, Y MATSUZAKI
    LANGMUIR 9 1 19 - 21 1993年01月 [査読有り][通常論文]
     
    A water-insoluble, self-standing cast film of a DNA-lipid complex was prepared by mixing both aqueous solutions of anionic DNAs and cationic amphiphiles at a charge ratio of 1:1. Intercalation behaviors of dye molecules into a cast film of a DNA-lipid complex deposited on a quartz-crystal microbalance (QCM) was followed quantitatively by observing frequency changes of a QCM in an aqueous solution.
  • Y OKAHATA, Y MATSUNOBU, K IJIRO, M MUKAE, A MURAKAMI, K MAKINO
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 114 21 8299 - 8300 1992年10月 [査読有り][通常論文]
  • Y OKAHATA, K IJIRO
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 65 9 2411 - 2420 1992年09月 [査読有り][通常論文]
     
    A lipid-coated lipase was prepared by mixing aqueous solutions of lipase amd dialkyl amphiphiles: A hydrophilic surface of the enzyme is covered with a lipid layer, of which lipophilic two-long-alkyl tails solubilize the enzyme in hydrophilic organic solvents. The lipid-coated lipase was prepared in various conditions by changing hydrophilic head groups of lipid molecules, a ratio of lipid/lipase, and an origin of lipase; the complex prepared from nonionic amphiphiles and lipase D from Rhizopus delemar showed a high stability and a high enzymatic activity in hydrophobic organic solutions. The lipid-coated lipase catalyzed di- and triacylglycerol syntheses from monoacylglycerols and aliphatic acids in the homogenous and dry benzene solution in the presence of two pieces of molecular sieves (water: 80 ppm). The lipid-coated lipase could also catalyze ester exchange reactions in organic solvents with a small amount of water (250 ppm). Enzymatic activity was affected by a nature of organic solvents and a water content in organic solvents. The catalytic activity of the lipid-coated lipase was highly efficient compared with other enzyme systems such as the poly(ethylene glycol)-grafted lipase and the direct dispersion of lipase powder for glyceride syntheses in the dry organic solution.
  • K IJIRO, Y OKAHATA
    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS 18 18 1339 - 1341 1992年09月 [査読有り][通常論文]
     
    A DNA-lipid complex is readily prepared by mixing aqueous solutions of anionic DNA and cationic dialkyl amphiphiles, which thus forms a double helical structure and exhibits intercalation of dyes in chloroform solution.
  • K IJIRO, Y OKAHATA
    JOURNAL OF MEMBRANE SCIENCE 59 1 101 - 112 1991年06月 [査読有り][通常論文]
     
    A lipase-immobilized capsule membrane reactor was prepared: poly(p-aminomethyl)styrene (polyAMS) or poly(p-chloromethyl)styrene (polyCMS) was surface-grafted onto a porous nylon capsule membrane (diameter: 2 mm, membrane thickness: 5-mu-m) and a lipase was immobilized to the side-chains of the grafted polymers on the capsule. When the lipase-immobilized capsule containing a buffer solution in the inner aqueous core was immersed in an organic solution of lipophilic substrates, the following reactions were effectively catalyzed compared with reactions catalyzed by a native lipase in water-in-oil emulsions: (i) syntheses of trilaurin from lauric acid and monolaurin, (ii) ester exchange reactions between tricaprylin and lauric acid, and (iii) hydrolyses of trilaurin. The catalytic reactions occur at the interface between the inner aqueous phase and the outer organic phase of the capsule membrane, where the lipase is protected from the organic solvents by the soaked buffer solution from inside. The reactivity of enzymes is affected largely by the lipophilicity of the polymer chains (polyAMS or polyCMS) grafted on the capsule and the polarity of the outer organic solvent.
  • Y OKAHATA, T TSURUTA, K IJIRO, K ARIGA
    THIN SOLID FILMS 180 65 - 72 1989年11月 [査読有り][通常論文]
  • Y OKAHATA, T TSURUTA, K IJIRO, K ARIGA
    LANGMUIR 4 6 1373 - 1375 1988年11月 [査読有り][通常論文]
  • Y OKAHATA, K IJIRO
    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS 20 1392 - 1394 1988年10月 [査読有り][通常論文]
  • Y OKAHATA, Y FUJIMOTO, K IJIRO
    TETRAHEDRON LETTERS 29 40 5133 - 5134 1988年 [査読有り][通常論文]
  • Y OKAHATA, K IJIRO
    JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 1 1 91 - 96 1988年01月 [査読有り][通常論文]

書籍

  • バイオミメティクス・エコミメティクス ー持続可能な循環型社会へ導く技術革新のヒントー
    居城邦治 (担当:分担執筆範囲:バイオミメティクス・インフォマティクスを支えるナノテクノロジー)
    シーエムシー出版 2021年01月
  • Stimuli-Responsive Interfaces -Fabrication and Application-
    Hideyuki Mitomo, Kenichi Niikura, Kuniharu Ijiro (担当:分担執筆範囲:Stimuli-responsive structure control of gold nanoparticle assembly)
    Springer 2016年11月 127-145
  • 生物模倣技術と新材料・新製品開発への応用
    三友秀之, 居城邦治 (担当:分担執筆範囲:生物の持つ発色メカニズムとその応用展開)
    技術情報協会 2014年07月
  • ソフトナノテクノロジーにおける材料開発
    シーエムシー出版 2011年
  • 次世代バイオミメティクス研究の最前線-生物多様性に学ぶ-
    シーエムシー出版 2011年
  • 現代界面コロイド科学の事典
    丸善株式会社 2010年
  • 自己組織化ハンドブック
    エヌ・ティー・エス 2009年
  • 超分子サイエンス＆テクノロジー－基礎からイノベーションまで－
    エヌ・ティー・エス 2009年
  • 金属ナノ・マイクロ粒子の形状・構造制御技術
    シーエムシー出版 2009年
  • バイオナノプロセス
    シーエムシー出版 2008年
  • 量子ドットの生命科学領域への応用
    ㈱シーエムシー出版 2007年
  • バイオとナノの融合Ⅱ-新生命科学の応用-
    北海道大学出版会 2007年
  • 自己組織化ナノマテリアル フロンティアテクノシリーズNo.9 -フロントランナー８５人が語るナノテクノロジーの新潮流-
    フロンティア出版 2007年
  • 自己組織化ナノマテリアル フロンティアテクノシリーズNo.9 -フロントランナー８５人が語るナノテクノロジーの新潮流-
    フロンティア出版 2007年
  • Application of Quantum Dot in Life Science
    2007年
  • 進化する有機半導体 有機エレクトロニクス創成へ向けた光・電子機能デバイスへの応用最前線
    エヌ・ティー・エス 2006年
  • ソフトナノテクノロジー -バイオマテリアル革命-
    ソフトナノテクノロジー -バイオマテリアル革命- 2005年
  • 超分子科学－ナノ材料創製に向けて－
    化学同人 2004年
  • Nanotechnology toward the Organic Photonics
    Nanotechnology toward the Organic Photonics 2002年
  • Studies in Surface Science and Catalysis 132
    Elsevier Science B. V. 2001年
  • Studies in Surface Science and Catalysis 132
    Elsevier Science B. V. 2001年

講演・口頭発表等

  • Self-Assembly of Gold Nanoparticles in Solution  [招待講演]
    Kuniharu Ijiro
    RIES-CEFMS Symposium 2022年12月
  • Biomimetic self-assembly of nanoparticles in solutions  [招待講演]
    Kuniharu Ijiro
    9th NaBIS 2022年11月 口頭発表（招待・特別）
  • 高分子を用いた刺激応答性プラズモニック金ナノ構造体の展開  [招待講演]
    居城邦治
    高分子学会第47回中国四国地区高分子講座 2021年12月 口頭発表（招待・特別）
  • Stimuli-Responsive Assemblies of Gold Nanopaericles and those applications  [招待講演]
    Kuniharu Ijiro
    International Conference on Materials Science and Engineering (Materials Oceania 2020) 2021年10月 口頭発表（招待・特別）
  • Stimuli-Responsive Gold Nanoparticles Assembly and Those Applications  [招待講演]
    Kuniharu Ijiro
    The 1st Australia-Belgium-Japan joint symposium on excitonics and cellular communication 2019年10月 口頭発表（招待・特別）
  • Self-Assembly of Rod-Shaped Au Nanoparticles and those Plasmonic Functions  [招待講演]
    Kuniharu Ijiro
    15th IUPAC International Conference on Novel Materials and their Synthesis (NMS-XV) 2019年09月 口頭発表（基調）
  • DNA Brush-Directed Aligning Self-Assembly of Gold Nanorods as Photonic Nanomaterials  [招待講演]
    Kuniharu Ijiro
    16th European Conference on Organized Films (ECOF16) 2019年07月 口頭発表（招待・特別）
  • バイオミメティクスへの取り組みについて  [招待講演]
    居城邦治
    機能性フィルム研究会夏季特別研修会 2019年07月 口頭発表（招待・特別）
  • Stimuli-Responsive Gold Nanoparticle Assembly and Those Applications  [招待講演]
    Kuniharu Ijiro
    10th International Conference on Materials for Advanced Technologies (ICMAT 2019) 2019年06月 口頭発表（招待・特別）
  • Development of Stimuli-Responsive Gold Nanostructure Assembly and those Applications  [通常講演]
    居城 邦治
    14th IUPAC International Conference on Novel Materials and their Synthesis (NMS-XIV) 2018年10月 口頭発表（基調）
  • ナノ粒子集積体のボトムアップファブリケーションとバイオ・フォトニクスへの応用  [招待講演]
    居城 邦治
    日本化学会北海道支部2018年夏季研究発表会 2018年07月 口頭発表（招待・特別）
  • 刺激応答性金ナノ構造集積体の創製と応用  [招待講演]
    居城 邦治
    日本化学会 第98春季年会 (2018) 2018年03月 口頭発表（招待・特別）
  • DNA Brush-Directed Alignment of Extensive Gold Nanorod Arrays as Plasmonic Nanomaterials  [招待講演]
    居城 邦治
    The 15th Pacific Polymer Conference (PPC-15) 2017年12月 口頭発表（招待・特別）
  • Active gap SERS with plasmonic nanostructures on hydrogels for the sensitive detection of biomacromolecules  [招待講演]
    居城 邦治
    8th International Conference and Exhibition on Lasers, Optics & Photonics 2017年11月 口頭発表（招待・特別）
  • Reversible pH or temperature stimulus-response self-assembly of nanoparticles  [招待講演]
    居城 邦治
    2017 RIES-CIS Symposium 2017年10月 口頭発表（招待・特別）
  • Self-assembled Nanoparticles as Photonic and Biological Nanomaterials  [招待講演]
    居城 邦治
    International Symposium on Materials for Chemistry and Engineering (IMCE 2017) 2017年02月 口頭発表（基調）
  • DNA Brush-Directed Self-Assembly of Gold Nanorods into Vertically Aligned Arrays  [招待講演]
    Kuniharu Ijiro, Satoshi Nakamura, Hideyuki Mitomo, Yasutaka Matsuo, Kenichi Niikura
    The 11th SPSJ International Polymer Conference (IPC 2016) 2016年12月 口頭発表（招待・特別）
  • Salmon DNA-based Preparation of Nanomaterials  [招待講演]
    居城 邦治
    The 17th Chitose International Forum on Photonics Science & Technology (CIF17) 2016年11月 口頭発表（招待・特別）
  • DNA Brush-Directed Vertical Alignment of Au Nanorod  [招待講演]
    Satoshi NAKAMURA, Hideyuki MITOMO, Yasutaka MATSUO, Kenichi NIIKURA, Kuniharu IJIRO, Andrew Pike
    12th IUPAC International Confrence on Novel Materials and their Synthesis(NMS-XII) 2016年10月 口頭発表（招待・特別）
  • ダイナミックなナノ粒子アセンブリングによる生体分子の表面増強ラマン散乱計測  [招待講演]
    居城 邦治
    日本分析化学会第65年会 2016年09月 口頭発表（招待・特別）
  • バイオテンプレートを用いたナノ構造組織体の設計  [招待講演]
    居城 邦治
    第65回高分子討論会 2016年09月 口頭発表（招待・特別）
  • Self-assembled 2D Monolayers and 3D Vesicle of Au Nanoparticles for Photonic and Biomedical Applications  [招待講演]
    居城 邦治
    KJF-ICOMEP 2016 2016年09月 口頭発表（招待・特別）
  • Self-assembled alignment of nanorod by using DNA brush  [招待講演]
    Kuniharu Ijiro, Satoshi Nakamura, Hideyuki Mitomo, Andrew Pike, Yasutaka Matsuo, Kenichi Niikura
    SPIE Optics + Photonics 2016年08月 口頭発表（招待・特別）
  • DNA brushes as functional interfaces for bio/nano applications  [招待講演]
    Kuniharu Ijiro, Hideyuki Mitomo, Satoshi Nakamura, Yasunobu Suzuki, Asumi Eguchi, Yasutaka Matsuo, Kenichi Niikura
    The First International Symposium on Advanced Soft Matter 2016年06月 口頭発表（招待・特別）
  • Self-Assembled Vesicles and Monolayers Prepared by Gold Nanoparticles and their SERS Applications  [招待講演]
    居城 邦治
    1st Student Winter WorkshopMaison France-Japan University de Strasbourg 2016年03月 口頭発表（招待・特別）
  • Active Gap SERS for the Sensitive Detection of Biomacromolecules with Gold Nanoparticles on Hydrogels  [招待講演]
    K. Ijiro, H. Mitomo, K. Horie, Y. Matsuo, K. Niikura
    JOINT WORKSHOP Frontier 2015 2015年12月 口頭発表（招待・特別）
  • Self-assembly of nanoparticles: beyond the molecular scale  [招待講演]
    居城 邦治
    The 3rd International Symposium on AMBITIOUS LEADER’ PROGRAM Fostering Future Leaders to Open New Frontiers in Materials Science 2015年11月 口頭発表（招待・特別） Akira Suzuki Hall, Hokkaido Univ.
  • Nanoparticle self-assembly for bio applications  [招待講演]
    居城 邦治
    2015 RIES-CIS Symposium 北海道大学電子科学研究所・台湾国立交通大学合同シンポジウム 2015年11月 口頭発表（招待・特別）
  • Hydrogel-Based Active Gap Control of Gold Nanoparticle-Assembly for Surface-Enhanced Raman Scattering Measurement of Macromolecules  [招待講演]
    居城 邦治
    11th IUPAC International Conference on Novel Materials and their Synthesis (NMS-XI) 2015年10月 口頭発表（招待・特別）
  • Plasmonic nanostructures based on self-assembled nanoparticles for biosensing  [招待講演]
    居城 邦治
    第76回応用物理学会秋季講演会シンポジウム 2015年09月 口頭発表（招待・特別）
  • Gold Nanoparticle Vesicles and Those Sensing and Biological Applications Based on Plasmonic Properties  [招待講演]
    Kuniharu Ijiro, Jinjian Wei, Yasutaka Matsuo, Hideyuki Mitomo, Kenichi Niikura
    KJF International Conference on Organic Materials for Electronics and Photonics 2015 (KJF-ICOMEP 2015) 2015年09月 口頭発表（招待・特別）
  • Polymer Network Based Tunable Plasmonic Device Using Nanoparticles  [招待講演]
    居城 邦治
    Japan-Taiwan Bilateral Polymer Symposium 2015 2015年09月 口頭発表（招待・特別）
  • Nanoparticle-based biomimetic functional materials  [招待講演]
    居城 邦治
    SPIE Optics + Photonics 2015 2015年08月 口頭発表（招待・特別）
  • ハイドロゲルを用いたチューナブルプラズモン共鳴とラマン分光への応用  [招待講演]
    居城 邦治
    日本学術振興会「先端ナノデバイス・材料テクノロジー第151委員会」平成２６年度 第1回研究会 ハイスループット材料分科会研究会 合同研究会 2015年07月 口頭発表（招待・特別）
  • タンパク質やナノ粒子の自己組織化によるナノカプセルの作製とそれらのバイオ・フォトニック応用  [招待講演]
    居城 邦治
    第一回新しい原子分子組織化物質・材料創出に向けた光・量子ビーム応用技術調査専門委員会 2015年05月 口頭発表（招待・特別）
  • 生物の動的構造色をヒントにした表面増強ラマン散乱基板の作製  [招待講演]
    居城 邦治
    日本化学会 第95春季年会 2015年03月 口頭発表（招待・特別）
  • Gold nanoparticle vesicles and those unique photonic properties  [招待講演]
    居城 邦治
    7th french-japanese joint workshop On FRONTIER MATERIALS 2014年12月 口頭発表（招待・特別）
  • 分子からナノ粒子へと展開する自己組織化  [招待講演]
    居城 邦治
    第14回 東北大学多元物質科学研究所研究発表会 2014年12月 口頭発表（招待・特別）
  • Fabrication of Nanoparticle Vesicles beyond Molecular Self-assembly  [招待講演]
    居城 邦治
    17th SNU-HU Joint Symposium Satellite "Frontiers in Chemical Sciences 2014 @ SNU & HU" 2014年11月 口頭発表（招待・特別）
  • The synthesis and bio/nano applications of DNA brushes  [招待講演]
    居城 邦治
    SPIE Optics + Photonics 2014 2014年08月 口頭発表（招待・特別）
  • ゲル表面への金属ナノ構造の固定化と動的構造色への応用  [招待講演]
    居城 邦治
    表面技術協会 2014年北海道夏期セミナー"自然に学ぶ表面処理" 2014年08月 口頭発表（招待・特別）
  • Nanoparticle Vesicles toward Biosensing and Drug Carrier  [招待講演]
    居城 邦治
    Synthetic Biology Meeting 2013年07月 口頭発表（招待・特別）
  • Self-assembly of Nanoparticles toward Biosensing and Drug Carrier  [招待講演]
    居城 邦治
    1st Conference of JSPS Core to Core Program 2013年06月 口頭発表（招待・特別）
  • Nanoparticle vesicles: preparation and applications in biosensing and drug delivery  [招待講演]
    居城 邦治
    Discussion Symposium on Artificial Life and Biomimetic Functional Materials 2013年05月 口頭発表（招待・特別）
  • Gold nanoparticle vesicles and their optical and biological applications  [招待講演]
    居城 邦治
    Rennes Frontier 2012 5th frence-japanese joint workshop on Frontier Materials 2012年12月 口頭発表（招待・特別）
  • Self-assembly of Nanoparticles for Optical and Biological Applications  [招待講演]
    居城 邦治
    RIES-CIS Symposium 2012年10月 口頭発表（招待・特別）
  • Room temperature coulomb blockade in a DNA-templated metal/polymeralternated hybrid nanowire  [通常講演]
    Kuniharu Ijiro, Guoqing Wang, Hirofumi Tanaka, Liu Hong, Yasutaka Matsuo, Kenichi Niikura, Masuhiro Abe, Kazuhiko Matsumoto, Takuji Ogawa
    2012 Optics + Photonics, SPIE 2012年08月 口頭発表（招待・特別）
  • Fabrication of functional nanowires by DNA-mediated self-assembly  [招待講演]
    居城 邦治
    imec Handai International Symposium 2012年06月 口頭発表（招待・特別）
  • 生体分子の分子認識を利用した機能性金属ナノ構造の自己組織化的作製  [招待講演]
    居城 邦治
    第114回 KARCコロキウム 2012年03月 口頭発表（招待・特別）
  • DNA-conjugated silver nanoparticles for fluorescence and Raman scattering dual-modal imaging  [招待講演]
    居城 邦治
    12th Chitose International Forum on Photonic Science & Technology (CIF’12) 2011年10月 口頭発表（招待・特別）
  • DNA-templated bottom-up fabrication of conductive nanowires  [招待講演]
    居城 邦治
    2011 Taiwan-Japan Bilateral Polymer Symposium (TJBPS'11) 2011年09月 口頭発表（招待・特別）
  • DNA-assisted fabrication of luminescent and Raman active silver nanoparticles for dual-modal bioimaging  [招待講演]
    居城 邦治
    SPIE Optics + Photonics 2011 2011年08月 口頭発表（招待・特別）
  • DNA-Tamplated Assembly of Azobenzene at the Air-Water Interface  [招待講演]
    居城 邦治
    PACIFICHEM 2010 2010年12月 口頭発表（招待・特別）
  • 同位体顕微鏡によるバイオイメージングの可能性  [招待講演]
    居城 邦治
    第30回 日本マグネシウム学会総会 2010年11月 口頭発表（招待・特別）
  • Introduction of RIES‐Hokkaido University and the Study of DNA‐templated Nano Device  [招待講演]
    居城 邦治
    The 3rd Workshop on FEL Science:"Emerging X‐ray Applications in Biological Systems‐II" 2010年10月 口頭発表（招待・特別）
  • Synthesis of DNA-nanoparticle/DNA-nanostructure for fabrication of single-electron device  [招待講演]
    居城 邦治
    SPIE Optics + Photonics 2010 2010年08月 口頭発表（招待・特別）
  • Base Sequence Specific Metallization of Single DNA Molecule for Application to Nano Devices  [招待講演]
    居城 邦治
    13th International Conference on Organized Molecular Films(LB13) 2010年07月 口頭発表（招待・特別）
  • Metallization of Single DNA Molecule for Application to Nano Devices  [招待講演]
    Kuniharu Ijiro, Aya Tanaka, Ken-ichi Niikura, Yasutaka Matsuo
    2010 Japan-Taiwan Bilateral Polymer symposium (JTBPS'10) 2010年07月 口頭発表（招待・特別）
  • Self-assembled Hierarchic Structures of Metal-Molecule Hybrids for Sensing and Electronic Devices  [招待講演]
    居城 邦治
    ICEP2010 2010年05月 口頭発表（招待・特別）
  • 生体の分子認識を利用した有機-金属バイオナノシステムの構築  [招待講演]
    居城 邦治
    ナノICTシンポジウム2010～ナノとバイオの融合が切り開く未来型ICT～ 2010年02月 口頭発表（招待・特別）
  • Fabrication of Molecular-Metal Hybrid Nanosystems based on Biomolecular Recognition  [招待講演]
    居城 邦治
    International Symposium on Engineering Neo-Biomimetics – Toward Paradigm Shift for Innovation – 2009年10月 口頭発表（招待・特別）
  • Base Sequence-Specific Metallization of Double-Stranded DNA for Bottom-Up Fabrication Process of Nanostructure  [招待講演]
    K. Ijiro, A. Tanaka, K. Niikura, Y. Matsuo
    International Symposium of Post-Silicon Materials and Devices Research Alliance Project 2009年09月 口頭発表（招待・特別）
  • Base Sequence-Specific Metallization of DNA for Bottom-Up Process of Nanostructure Fabrication  [招待講演]
    居城 邦治
    HYU-RIKEN Joint Workshop & FTC One Year Anniversary Celebration 2009年08月 口頭発表（招待・特別）
  • DNA-assisted fabrication of functional metal nanostructures  [招待講演]
    Kuniharu Ijiro, Aya Tanaka, Ayako Ishikawa, Ken-ichi Niikura, Yasutaka Matsuo
    SPIE Optics + Photonics 2009 2009年08月 口頭発表（招待・特別）
  • Fabrication of Nanowires by Base-Selective Metallization of DNA  [招待講演]
    居城 邦治
    Japan-Korea-China Mini-symposium on Nanotechnology, Biotechnology and Catalysis -Satellite Session- 2008年11月 口頭発表（招待・特別）
  • DNA Sequence-Selective Fabrication of Platinum Nanowires  [招待講演]
    居城 邦治
    AsiaNANO2008 (Asian Conference on Nanoscience and Nanotechnology) 2008年11月 口頭発表（招待・特別）
  • DNA Sequence Specific Fabrication of Metal Nanostructures  [招待講演]
    居城 邦治
    Korea-Japan Joint Forum (KJF) 2008 2008年10月 口頭発表（招待・特別）

その他活動・業績

特許

  • 特開WO 2012/115151:粒子集積体、粒子集積体の製造方法、光増強素子及び光化学反応を利用する装置  
    NATIONAL UNIVERSITY, CORPORATION, HOKKAIDO UNIVERSITY, IJIRO KUNIHARU, NIIKURA KENICHI, IYO NAOKI, NISHIO TAKASHI
  • 特開WO2007049494:パターニングされた物質の製造方法  2007年05月03日
    藪浩, 下村政嗣居城邦治, 松尾保孝, 山本貞明, 田中賢  
    WO2007/049494
  • 特開2006-207010:DNAを用いた透明電極の作製方法  2006年08月10日
    居城邦治, 佐藤壮人, 松尾保孝  
    特開2006-207010
  • 周期的な構造が形成された樹脂フィルムの製造方法
    特許公開２００８－２９６５０２
  • 3次元構造が形成された樹脂フィルムの製造方法
    特開2008-296481
  • 銀微粒子と核酸の複合体及びその製造方法
    特開2008-224274
  • 目的物質の核内送達用ベクター
    WO2007／102481
  • 炭素構造体の製造方法及び炭素構造体、並びに炭素構造体の集合体及び分散体
    特開2007-169148
  • 生体適合性および高体積変化能を有する組織体ならびにその作製方法
    特開2006-204813
  • 光記録媒体及び光多重記録方法
    特開2005-209330
  • ＤＮＡの無電解メッキによる金属細線構造の構築
    特開2005-120450
  • ＤＮＡ一分子の特異的塩基配列検出法
    特開2004-283098
  • 環状DNAの伸長固定化法
    特開2004-147537
  • 有機超薄膜とその累積体並びにその製造方法
    特開2004-099741
  • DNA分子の伸長固定化方法
    特開2003-135062

受賞

  • 2018年10月 14th IUPAC International Conference on Novel Materials and their Synthesis Distinguished Award 2018 for Novel Materials and their Synthesis
  • 2018年03月 公益社団法人 日本化学会 日本化学会学術賞
     刺激応答性金ナノ構造集積体の創製と応用 
    受賞者: 居城 邦治
  • 2016年09月 高分子学会 高分子学会三菱化学賞
     バイオテンプレートを用いたナノ構造組織体の設計 
    受賞者: 居城 邦治
  • 2016年02月 北海道大学 平成27年度教育総長賞
     
    受賞者: 居城 邦治
  • 2014年05月 公益社団法人 高分子学会 高分子学会賞
     ハニカムフィルムの生産技術とその応用 
    受賞者: 居城 邦治
  • 2007年11月 日刊工業新聞社主催、ＮＥＤＯ共催、中小企業基盤整備機構特別協力 第２回モノづくり連携大賞 モノづくり連携大賞
     北海道の地の利と人材を活かしたバイオとナノの連携プロジェクト―自己組織化ハニカム膜の製造技術と医療応用―

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2019年06月 -2024年03月 
    代表者 : 玉田 薫, 木戸秋 悟, 須川 晃資, 岡本 晃一, 居城 邦治
     
    課題１：超解像度超高速ライブイメージング用局在プラズモンシートの作製 Edgeの尖った銀ナノキューブ（立方体）について単層で大面積(数mm四方)の膜を作製することに成功した。さらに水ーブタノール混合溶媒系界面での銀ナノプリズムの二次元自己組織化が、ブタノールの界面への過剰吸着とそれに起因する界面での対流に誘発されることを明らかにした。電磁場解析計算では、金属薄膜上に金属ナノ構造を配置すれば光の共鳴ピークが著しく先鋭化し、Q値が約10倍、発光増強換算で約40倍の電場増強が得られることが明らかになった。さらに集光シミュレーションを行ったところ、通常の材料の半分以下の集光スポットが得られ、高分解イメージングの可能性が示唆された。 課題２：細胞接着ナノ界面の創製と分子ダイナミクスの直接観察 細胞接着の初期段階において、これまでに報告されていない新たな繊維状新生接着体の形成を発見した。この構造体は細胞が基板に接触した直後にのみ放射状に現れ、細胞が成熟した接着斑を形成し伸展を始めると消失する。またこの構造体はフィブロネクチン処理基板など細胞接着性表面では現れず、細胞が接着しにくい基板でのみ細胞の剥離を抑えるように現れる。これは局在プラズモンシートによる高解像度・高速イメージングによって初めて可視化されたもので、これについて論文発表し、プレス発表をした。さらに今後課題３で実施する医療応用（幹細胞/がん細胞の動態診断）の試験観察を始め、細胞腫によって界面での深さ方向の動き（ダイナミクス）に違いがあることを見出した。 その他、国際共同研究の成果として、台湾師範大学との共同研究において、ペロブスカイト量子ドットを使った発光メモリーデバイスの開発に成功し、その成果についてNature Comm.に発表した。台湾国内では20社を超える新聞発表/TV報道がなされ、日本へもYahooニュースとして逆輸入され注目を集めた。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2012年06月 -2017年03月 
    代表者 : 細田 奈麻絵, 前田 浩孝, 穂積 篤, 浦田 千尋, 重藤 暁津, 松尾 保孝, 和田 健彦, 北島 博, 居城 邦治
     
    生物のサブセルラー・サイズ構造の階層性は、防汚（ナメクジや蓮の葉）、自己治癒（葉の表面）、可逆的接着性（昆虫の脚裏）など多様な機能を発現している。本研究では、生物物理・材料/表面科学の視点からそのしくみを解明し、革新的な材料開発を目指した。中間評価以降は、特にエレクトロニクス実装への応用が可能な基盤技術（可逆的接合、セルフアライメント技術、防汚/防錆性付与、自己治癒による長寿命化、放熱特性の向上など）を重点項目として位置付け研究を展開した。これにより、人工材料にない優れた多層膜皮膜の開発、全く新しい発想による泡を利用したセルフアライメント、可逆的な接着機構の実現などほぼ計画通り達成できた。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2012年06月 -2017年03月 
    代表者 : 下村 政嗣, 長谷山 美紀, 石田 秀輝, 針山 孝彦, 森 直樹, 劉 浩, 大園 拓哉, 穂積 篤, 細田 奈麻絵, 齋藤 正男, 野村 周平, 松尾 保孝, 居城 邦治
     
    進化適応の結果である生物多様性を、持続可能性をもたらす“壮大なるコンビナトリアル・ケミストリー”と位置つけることで、自然史学、生物学、農学、材料科学、機械工学、情報学、環境政策学、社会学等の研究者による我が国では類を見ない異分野連携研究ネットワークを構築することにより、ニーズ・シーズ・マッチングと発想支援が可能となる「バイオミメティクス・データベース」を編纂し、情報科学による生物から工学への技術移転が可能であることを実証した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2010年 -2012年 
    代表者 : 居城 邦治
     
    本研究の目的は、独自の環状構造を有するDNAを塩基選択的に金属化することで負の屈折率を持った物質であるメタマテリアルを自己組織化的に作製することである。これまでミリ波や赤外線を対象にしたメタマテリアルが作られてきたが、微細加工限界のため可視光に対して負の屈折率を持つ構造は作れなかった。本提案では酵素合成した環状二重らせんDNAを部分的に金属化することで、理論的に可視光に負の屈折率を持つと予測されるsinglesplit-ringresonators(SSRRs)のサイズを制御して作製できる技術を確立することをめざし、poly(dG)・poly(dC)に結合したシスプラチンの還元によるプラチナナノワイヤーの作製手法を基本にして金属ナノギャップを作製した。これによりメタマテリアルを作製する要素技術を確立した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2010年 -2012年 
    代表者 : 居城 邦治, 佐野 健一, 新倉 謙一, 松尾 保孝, 島本 直伸, 三友 秀之
     
    単電子トランジスタは、劇的な低消費電力を可能とする素子として注目されている。室温での動作を可能にするためには、ソース電極とドレイン電極の間に直径は数nmの「クーロン島」(極小の導電性金属)をnmの精度で置く必要がある。しかしながら現在のフォトリソグラフィー技術ではこのような精密な構造を作ることは不可能である。そこで本研究では核酸DNAの分子認識を用いることで、自己組織化的にナノワイヤー-量子ドット-ナノワイヤー構造のような単電子トランジスタ構造を作製した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2007年 -2009年 
    代表者 : 新倉 謙一, 居城 邦治, 小暮 健太朗
     
    申請者は糖鎖提示量子ドットをプローブとして細胞がストレスに暴露した際の応答を、感度よく検出することを目的に研究を進めた。3年間の研究で主に以下の2点を明らかにすることができた。 1.GlcNAcを提示した量子ドットは小胞体に蓄積する傾向があり、重金属などで細胞にストレスを付加することでその蓄積量が増えることがわかった。これは細胞ストレスを蛍光量で定量できることを示すものである。 2.α-Glucoseを提示した量子ドットは、細胞の核内に蓄積することがわかった。ナノ粒子の核移行は医学的にニーズが高いため、多様な応用につながる発見である。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2007年 -2008年 
    代表者 : 新倉 謙一, 澤 洋文, 松尾 保孝, 居城 邦治
     
    ウイルスのタンパク質が自己集合して形成するウイルス様微粒子(virus-like particle : VLP)は、ウイルスゲノムを持たずにウイルスと同じ経路で細胞内へ導入されるため、ドラッグデリバリーシステムのキャリアー等として注目されている。私たちはVLPの持つ糖鎖認識性に着目し、糖鎖の分子認識を利用してウイルスの周辺に規則的に金属微粒子を配列させることを目的に研究を進めた。まず金微粒子にシアル酸を提示させる技術を確立した。このシアル酸提示金微粒子は非常に水への分散性が高く、ウイルスと結合させても沈殿するようなことはなかった。VLPとシアル酸を修飾した金ナノ粒子の複合体形成の電子顕微鏡像(STEM)を詳細に検討すると、VLPの表層に特異的に金ナノ粒子が結合している様子が観察された。また、紫外可視吸収スペクトルの長波長シフトには、金ナノ粒子表面のシアル酸の有無によって有意な差が生じたことから、溶液中でも金ナノ粒子がVLPに結合していることが示された。さらに金ナノ粒子濃度の上昇に伴いプラズモン吸収の長波長側への大きなシフトが測定された。これはウイルスを鋳型とした金ナノ粒子の結合により、三次元的なプラズモンのカップリングが起きたことを意味している。さらにウイルスと金微粒子の結合を促進するために、デキストランを添加した。この効果は高分子クラウディング効果と言われるが、金属微粒子と生体分子(この場合はVLP)の特異的な結合をクラウディング効果で成功させた初めての例である。本研究によってウイルス-金微粒子複合体が外部の光と共鳴するプラズモン共鳴体になりうることを証明できた。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2007年 -2008年 
    代表者 : 居城 邦治, 新倉 謙一, 松尾 保孝
     
    高度情報通信社会を将来にわたって持続的に発展させるためには、電子デバイスの微細化と高性能化を低コストでさらに進めなければならないが、これは従来の半導体デバイスの延長線上では実現が困難であり、それに代わる新しいナノデバイスの開発が不可欠である。そこで本研究では単一分子で動作する極微細ナノデバイスの作製を目標として、DNAの自己組織化と無電解メッキを応用することで単一分子デバイスを作製する手法の開発を行った。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2006年 -2008年 
    代表者 : 下村 政嗣, 居城 邦治, 松尾 保考, 藪 浩
     
    本研究では、ボトムアップナノテクノロジ-のキ-技術である自己組織化によるナノ・ミクロ構造形成と、成熟した技術である無電解メッキを組み合わせることで、全湿式プロセスによるラピッドプロトタイピングが可能であることを示すことができた。また、マイクロメ-タ-スケ-ルの細孔を有するハニカム様多孔質フィルムが赤外領域でフォトニック結晶になりうることを確認しており、細孔径のサブミクロン化によって可視光領域でのフォトニック結晶が可能となる。金属化により、高屈折率化と力学強度にすぐれた材料が期待される。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2005年 -2006年 
    代表者 : 居城 邦治, 新倉 謙一, 松尾 保孝
     
    これまで申請者は、DNA水溶液上にカチオン性の両親媒性化合物を展開し、静電的相互作用により気水界面に形成したDNA分子とのポリイオン複合膜をLangmuir-Blodgett(LB)法により、単分子膜に流動性を持たせた状態で固体基板上に移し取ると、溶液中ではランダムコイル形状であったDNA分子が伸長して固定化されることを見い出してきた。伸長・固定化された個々DNAA分子は長さ解析の結果、単一分子であることが明らかとなり、また二重らせんDNA鎖をほぼ伸び切り構造で2次元に配列することができることを示した。しかし、DNAが伸長するメカニズムは明らかになっていない。そこで研究では、これまで未開拓であったメニスカスにおける高分子鎖のダイナミクスの計測技術の開発を通じて、LB法によるDNAの伸長機構を明らかにすることを目的とした。 DNAが気体・液体・固体の三相が交差するメニスカスにおいて伸長されることから、メニスカスでのDNA分子の運動を観察できる蛍光顕微鏡システムを構築した。このシステムを用いてDNA水溶液上にジアルキルアンモニウム塩(2C_<18>N^+2C_1)を展開することで気液界面に形成した2C_<18>N^+2C_1/DNAポリイオン複合単分子膜の観察を行った。その結果、糸まり状のDNAがメニスカス境界部分で数秒間滞留し、その後基板状に伸長した状態で固定化されていく様子が観察された。一方、溶液中のDNAはメニスカス部分で対流を行うだけで固定化されないことが分かった。一度固定化した伸長DNAを90度回転させて引き上げを行ったところ、部分的に強固な接着点が存在することが解明された。 また、山形大学・佐野研究室との班内共同研究によって、Langmuir-Blodgett(LB)法により、DNA分子の伸長固定化を利用することで、これまで伸長・配向化が困難とされてきたカーボンナノチューブの伸長固定化を行った。DNAとカーボンナノチューブを水溶液中で混合し、DNAが巻き付いたカーボンナノチューブ複合体を作製し、これをLB法により固体基板上に伸長・固定化できることがわかった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2004年 -2005年 
    代表者 : 下村 政嗣, 居城 邦治, 田中 賢, 藪 浩
     
    本研究の課題は、水滴を鋳型として自己組織的に形成されるハニカム状多孔質膜の上面を粘着テープ等で剥離することで、突起状の構造体を形成し、これをメッキすることにより、電界放出素子への応用を検討することにある。 期間中にハニカム状多孔質膜の上面を剥離した後無電解メッキを行うことにより、銀等の金属からなるピラー状構造体が形成できることを見いだした。さらに無電会メッキの手法を応用することで、酸化亜鉛等の金属酸化物半導体をメッキできることを見いだした。これらの成果により特許を1報出願した。 さらに、単なる金薄膜あるいは作製した金属ナノピラー構造と、金をスパッタリングしたITO基板とを、100〜200μm程度のギャップを空けて設置し、減圧した後、その間に1〜100Vの電圧を引加した時に、どの程度電流が流れるかを、微小電流・抵抗測定器によって測定したところ、薄膜の場合よりもピラー構造の場合の方が、約3倍程度電流が流れることを見いだした。この成果により、特許を1報出願した。 以上の結果より、本研究課題の目標であった、自己組織化によるピラー構造の形成と、その金属化により、電界放出素子の作製の基本動作確認が出来た。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2004年 -2005年 
    代表者 : 居城 邦治, 下村 政嗣, 田中 賢, 新倉 謙一, 松尾 保孝, 藪 浩
     
    DNAマイクロアレイは遺伝子解析にとって大変重要な基盤技術である。多量解析のためにはDNAアレイの高度集積化が急務であるが、DNAスポットの間隔を20μm以下にすることは現在の光リソグラフィーによる合成型やスポッターを用いた貼り付け型の技術では困難である。従来のトップダウン法によるDNAマイクロアレイ作製技術に代わり、DNAの塩基対形成による分子認識による100nm間隔のDNA配列技術の開発を目指す。具体的には遺伝子の検出方法として知られているFISH法(Fluorescence In-Situ Hybridization)を使うことで伸長固定化した単一DNA分子でプローブDNAのナノアレイ化を行い、さらにそれらナノアレイを並べて階層化することで高度集積化を図り、従来の1000分の1の大きさのDNAチップの作製を目標とする。 特定の間隔のDNA配列技術の開発のモデル実験として、40塩基の20塩基ずつが相補的な2種類の40塩基オリゴマーからなるHalf-sliding DNAの多重会合体形成について検討した。AFMによる観察と環状DNA以外のDNAを加水分解するexonucleaseVによる酵素反応の結果から、TE中で形成されたDNA多重会合体は直鎖状構造であるのに対し、金属イオン下で形成されたものは環状構造であることがわかった。直鎖状のDNA多重会合体は剛直なロッド構造のため多重会合体の分子内会合が起こらないのに対し、多重会合体形成時に金属イオンが存在するとHalf-sliding DNAユニットの一本鎖部分が金属イオンによって柔軟になり環状DNAを形成しやすくなったと考えられる。以上から、多重会合体の形成においては金属イオンの有無が直鎖状と環状の形成を決めていることがわかった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2003年 -2004年 
    代表者 : 田中 賢, 下村 政嗣, 居城 邦治
     
    Poly(2-methoxyethyl acrylate)(PMEA)表面は、細胞に対する活性化が軽微であり、表面に吸着したタンパク質の構造変化が小さいことを明らかにした。PMEA中の水の構造を調べたところ、-100℃からの昇温過程で水のコールドクリスタリゼーション(CC)に由来する発熱ピークが-40℃付近に観測された。一方、生体適合性の劣る高分子ではこのような水の存在は認められなかった。CCとして観測される中間水量が生体適合性に強く影響を及ぼしていることを見いだした。この中間水は、高分子表面の自由水と不凍水との界面に存在し、また、高い分子運動性を有するPMEA鎖に弱く束縛され、低温下でも分子運動性の高い水であることを明らかにした。また、PMEAと同様の中間水を有する生体適合性高分子:poly(tetrahydrofurfuryl acrylate)(PTHFA)、poly[2-(2-ethoxyethoxy)ethyl acrylate](PEEA)を新規合成した。PEEAおよびその類似体は下限臨界共溶温度を有することがわかった。さらに、高分子溶液を高湿度下でキャストするだけで、孔径の均一な多孔質薄膜が様々な生体適合性材料で作製できることを利用して、その多孔質薄膜の3次元構造制御に成功した。体内埋め込み型治療器具表面にもこの膜を作製することができた。多孔質薄膜表面に粘着テープを張って剥離することによって、剥離破断面(テープ側と基板側)にナノピラー構造を作製した。ナノピラー構造の前駆体となる多孔質薄膜の材質、孔径、膜厚や剥離方法を変えることで、突起の長さや太さ、間隔の制御が可能であった。これらの表面で神経系・消化器系・血管系細胞を培養したところ、正常細胞の増殖性や機能を上昇させることに成功した。一方、がん細胞の増殖性・細胞死を制御できることを見いだした。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2002年 -2004年 
    代表者 : 下村 政嗣, 居城 邦治, 田中 賢, 山本 貞明, 松尾 保孝, 藪 浩, 澤田石 哲郎
     
    本研究の目的は、高分子溶液をキャストした際に結露した水滴を鋳型として生成されるハニカム構造化膜の空孔中に発光性の微粒子を封入し、面状に発光するデバイスを作製することである。今年度は色素を分散させた微粒子作製と、そのハニカム膜への導入を行った。 色素とポリスチレンを溶かしたテトラヒドロフラン(THF)溶液に貧溶媒である水を加え、THFを蒸発させてやると、300nm前後の色素を担持したポリスチレン微粒子が形成されることを見出した。 ハニカム膜は疎水的な材料から作製されているため、その表面は高い撥水性を示す。従って微粒子の水分散液を導入しようとすると全く濡れることが出来ない。ここでハニカム膜の表面を親水化するために、UV-オゾン処理を行う方法を考案した。UV-オゾン処理により表面が親水化され、ハニカム状の空孔に微粒子が導入されやすい状態となった。 空孔中に微粒子を導入する方法はキャスト法やディップコート法などの方法が考えられるが、これらの方法では連続処理に向かなかったり、粒子を十分導入できない等の問題がある。そこで微粒子分散液を2枚のスライドガラスでははさみ、一方のスライドガラスに親水化したハニカム膜を固定し、一方のスライドガラスを一定速度でスライドさせる方法を考案した。その結果、非常に効率よく、よりパッキングしたハニカム-微粒子ハイブリッド構造が家試製された。色素を励起すると孔部分が明るく光っていることが観察され、面状の高分子デバイスが作製できた。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2001年 -2004年 
    代表者 : 岡畑 恵雄, 森 俊明, 川崎 剛美, 古澤 宏幸, 居城 邦治, 金城 政孝
     
    DNAの高度配向化薄膜の作製を目的として以下の研究を行った。 1)DNAとカチオン性脂質からDNA-脂質複合体を作製し、ホットプレス法により、透明で丈夫なDNA配向化薄膜を得た。DANのフィルム中での配向性についてはX線解析、偏光解析により定量化した。 2)DANフィルムをくし形電極上にのせてDAN鎖方向の電気伝導度を測定し、10^<-3>S cm^<-1>という値を得た。この値はワイドギャップの半導体に相当する値であり、DNA鎖はアル程度は導電性を持っていることがわかった。 3)DANフィルムに色素をインターカレートし、可視光照射により色素を励起すると光誘起電流が観察できた。この事を利用して、有機ELフィルムを作製した。具体的には、DANをホール輸送相として、カチオン性脂質にπ電子を多く持つ芳香族化合物を導入して電子輸送相として利用し、ルテニウム型の色素をインターカレートすると、青色の発光を観察した。 4)DNA一分子を基板上に引き上げて、一分子の電導性をAFMチップを用いて観察した。電導性を向上させるために、金属メッキを行うと電導性が飛躍的に向上した。 DAN一分子の水溶液中での挙動を観察するために、正立型蛍光相関分光顕微鏡を試作し、DNA一分子の水溶液中での「ゆらぎ」を測定した
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2002年 -2003年 
    代表者 : 居城 邦治, 田中 賢, 下村 政嗣
     
    電子部品のダウンサイジングや高密度メモリーの作製のために、電極の極微細加工技術の開発が急務となっている。これまで微細電極は光リソグラフィーにより作られてきたが限界に近づきつつある。従来のトップダウン方式にかわり、本申請では二重らせんDNAに見られる相補的塩基対形成による分子認識を利用して、自己組織化により半導体微粒子を配向・配列させる手法の実証及び確立を目指す。具体的には、1本鎖もしくは二重らせんDNAを固体基板に伸張固定化し、無電解メッキもしくは核酸塩基を修飾した半導体ナノ微粒子の固定化により極細線電極およびナノPN接合を作製し、ナノデバイスの開発を目的とする。 上記の目的に従って、本年度までに下記の結果を得た。 1 単一DNA分子の伸張固定化の最適化 DNA水溶液上にカチオン性脂質単分子膜を形成し、気水界面で作製したDNA-脂質複合体膜をフィルムバランスを用いてガラス基板に移し取り、蛍光顕微鏡にてDNA分子の形状を観察した。DNAの伸張が最適になるよう、累積表面圧、累積速度、DNA水溶液濃度、などの累積条件を検討した。その結果、高い再現性でDNA分子を伸張・固定化できるようになった。 2 DNA分子上への銀ナノ微粒子の析出 DNAに白金錯体シスプラチンを結合させ還元した後に固体基板に伸長固定化した。これを無電解メッキ溶液に浸すことで、DNA分子上に銀のナノ微粒子を析出させることに成功した。原子間力顕微鏡により観察したところ銀のナノ微粒子がDNAに沿って配列した細線構造が形成されたことを確認した。 3 ナノPN接合の作製のためのナノ微粒子の合成 伸長したDNA分子上に微粒子を並べるために核酸ポリマーから成る微粒子を合成した。核酸ポリマーとカチオン性界面活性剤からなるポリイオンコンプレックスを改良した再沈殿法により微粒子化した。その結果、分散度の低い直径が64ナノメートルの微粒子を得ることに成功した。 今後は、半導体を包埋した核酸ポリマー微粒子を作製し、伸長固定化したDNA上に銀ナノ微粒子とともにインテグレーションすることでナノPN接合を作製し、動作確認を行う予定である。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2001年 -2003年 
    代表者 : 田中 賢, 笹木 敬司, 居城 邦治, 下村 政嗣, 松下 通明, 藤堂 省
     
    本研究では、優れた生体適合性を有するポリメトキシチルアクリレートと光架橋性基を有するグリシジルアルクレートやエポキシシックロヘキシメチルアクレートとを用いて、フェムト秒レーザー照射による2光子吸収による3次元微細光ファブリケーションを利用したの微細加工技術によって加工された空間構造と高分子の自己組織化現象の両方を利用することで、これまで作製が難しかったナノレベルの空間構造と表面特性のパターニングを実現できた。パターンの孔径、膜厚、孔貫通・非貫通、孔の3次元構造制御を計画的に行うためのパラメーターを抽出できた。様々な生分解性高分子、生体適合性高分子が適用できるパターン化技術を確立した。血管内皮細胞はパターン表面でのみ伸展し、凸部に伸展する細胞は観察されなかった。アクチン染色の結果、パターン表面の幹部分に沿って細胞骨格の先端が伸びているのが観察された。一方、フラットフィルム上では細長い形態をとるものが多く観察され、アクチン染色の結果、伸展方向と平行に伸びる細胞骨格が観察された。さらに、微細なパターン構造が、血管内皮細胞・平滑筋細胞の接着形態、骨格タンパク質の構造、細胞外マトリックスの産生、増殖性に影響を与えていることが明らかになった。上記のパターンは培養基材として機能しており、血管内治療デバイスscaffoldとしての可能性が示唆された。また、パターン化フィルムは孔の貫通・非貫通が制御可能であり、積層傾斜膜状、中空糸状などに成型加工できることも見いだした。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2001年 -2002年 
    代表者 : 居城 邦治
     
    カーボンナノチューブやシクロデキストリンチューブやミセルの集合体などに見られるチューブ構造は、ナノメートルスケールで物質の輸送することができることから、大変注目されている。しかし、チューブ構造は長さがマイクロメートルに至るため、分子設計して全体を合成することは大変困難である。そこで環状構造体を積み重ねればチューブ構造が形成できると考えた。これまで我々は気水界面における核酸塩基対形成について研究を行ってきた。核酸塩基対の形成は相補的すなわち特異的であり、また方向性が制限されていることから、環状構造体の積み重ねの駆動力として使えると考えた。すなわち環状のオリゴヌクレオチドを用いることで塩基対形成によりチューブ構造が形成できると期待される。本申請の研究目的は、環状オリゴヌクレオチドを合成し、水溶液中や有機溶媒中において自己組織化によりチューブ構造を作製することである。交付期間内に環状オリゴヌクレオチドの合成法の確立とチューブ構造の作製条件を探索する。 上記の目的に従って、本年度は下記のことを行った。 1 環状オリゴヌクレオチドの合成 液相法で環状オリゴヌクレオチドを合成した。リン酸基を保護したままヌクレオチドを伸張し、環化反応を行い、その後リン酸基の保護基をはずして目的物を得た。今年度は環状オリゴチミン4量体、環状オリゴチミン6量体、環状オリゴチミン8量体、環状オリゴチミン10量体を合成した。 2 環状オリゴヌクレオチドの分子認識 合成した環状オリゴヌクレオチドを含む下水相表面に、アデニン界面活性剤の単分子膜を作製し、環状オリゴチミンの塩基対形成について検討したところ、ワトソン-クリック型の塩基対が形成することがわかった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2000年 -2001年 
    代表者 : 居城 邦治, 田中 賢, 下村 政嗣
     
    本研究の目的は、DNAの電子伝達能力を利用して、界面で起こるハイブリダイゼーションを検出しうる手法を開発しようとするものである。そのためには、界面で起こる塩基対形成について調べる必要があり、さらにDNAを介した光誘起電子移動反応を詳細に検討する必要がある。 1)界面で起こる塩基対形成の研究 本研究では界面に固定化したDNAを取り扱うため、様々な界面での塩基対形成を調べる必要がある。アルキル化核酸塩基は気液界面で単分子膜を作り、膜表面で相補的な塩基対を形成することがわかった。(Mol.Cryst.Liq.Crys.,371,33-36(2001),Mol.Cryst.Liq.Crys.,371,379-382(2001))また、原子間力顕微鏡のプローブ先端に核酸塩基を固定化し、固体基板上に存在する核酸塩基との塩基対形成を水中にて力として計ることに成功した。(Mol.Cryst.Liq.Crys.,371,151-154(2001),Colloid and Surfaces A :Physicochem Eng.Aspects,198-200,677-682(2002))これらの結果より、気液界面、および固液界面においても、相補的な塩基対形成が起きることが示された。 2)DNAを介した電子移動測定 DNA上を電子が移動することを確認することが本研究で最も重要なことである。DNAからなるパターン化したフィルムを微小電極上に作製し、微小プローブ電極により導電性を測定した結果、導電性が観察された。(Mol.Cryst.Liq.Crys.,374,375-378(2001)) 3)塩基対のスタッキングを介した光誘起電子移動反応 電子ドナーと電子アクセプターをそれぞれ有する両親媒性化合物とDNAとのポリイオン複合単分子膜を気液界面に作製し、蛍光寿命からDNAを介した電子移動を測定した。その結果、1本鎖より2本鎖DNAの方がより電子移動を促進することがわかった。この結果より、光誘起電子移動反応によりハイブリダイゼーションを検出できることが示された。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1999年 -2001年 
    代表者 : 下村 政嗣, 田中 賢, 居城 邦治, 西川 雄大, KARTHAUS Olaf
     
    本研究の目的は、植物の光捕集系で見られるようなコヒーレントな光励起状態を人工的に作製することにある。この研究の特徴は、厳密に分子量とシークエンスが決定されているDNAの構造に着目し、それを鋳型とすることで、気水界面に形成される分子集合体である単分子膜を用いて一次元パイ電子集積体を作製することにある。3年間の研究成果を以下にしめす。 (1)DNAを鋳型とする1次元π電子系分子配列系の作製-ジアセチレンを含む核酸塩基単分子膜の鋳型光重合 水相に溶解した一本鎖DNAを鋳型として単分子膜の重合を行うために、トポタクティックな光重合性が知られているジアセチレン基を疎水鎖に導入した核酸塩基誘導体を新たに合成し、気液界面における核酸塩基間の分子認識と光重合を検討した。その結果、核酸塩基単分子膜が鋳型となるシングルストランドDNAとのワトソンクリック型ならびにフーグスティーン型の水素結合形成することを明らかにするとともに、ポリジアセチレンの重合度が鋳型DNAの塩基数に依存することを見いだした。これによりDNAを鋳型とすることで1次元π電子分子配列系の作製が可能となった。 (2)マクロ配向技術の確立-単一DNA分子の配向固定化 ポリジアセチレン系1次元π電子集積系の孤立化を最終的な目的として、ラングミュアー・ブロジェット法による単分子膜の移し取りを使った単一DNA分子の配向固定化を行った。マクロ配向技術の確立気液界面に形成される単分子膜を基板上に移し取る時に形成される流動配向場を利用して、鋳型となるDNA一分子を配向固定化することに成功した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2000年 -2000年 
    代表者 : 下村 政嗣, 岡畑 恵雄, 西 則雄, 居城 邦治, 田畑 仁, 大野 弘幸
     
    本調査は、核酸ならびに関連物質を分子性機能材料として新しく展開しようとしている生体機能関連化学、高分子化学、応用物理学、ならびに光化学の研究者と、単一分子検出を専門としている分光学、生物物理、物理光学の研究者が、核酸高分子の材料化の手法、構造評価、機能化について情報を交換し、DNAを分子情報と分子フォトニクスの機能をあわせもつ単一分子素子としての新しい展開の可能性を探るものである。核酸高分子を材料化しようとする試みは、分子組織化の技術と分子レベルでの構造観察技術の著しい展開を背景に、ここ数年、世界的に注目されはじめている。核酸高分子を機能性高分子としてとらえ、分子レベルで設計された分子性機能材料として展開するためには、LB法や自己組織化法などを用いて分子自身の組織化力を有効に利用して分子配列や配向制御を可能とする分子組織化技術や、レーザー光放射圧や原子間力などを用いた分子操作技術、などの発展が強く要求される。また、これらの技法を用いて作製した分子デバイスの分子レベルにおける構造評価には、走査型プローブ顕微などによる形態観察や分子間力などの物理パラメーターの測定、単一分子の分光学的測定が不可欠になる。このように、核酸高分子の分子レベルの組織化と構造評価法の開発は、学際的な共同研究によるアプローチを前提とした本調査によってはじめて可能となる。核酸の有する機能の最も特徴的なものは、きわめて選択性の高い塩基間での水素結合、インターカレーションと呼ばれる核酸塩基対間への物質の特異的な取り込み現象、などに基づく分子認識能である。本調査では、化学力顕微鏡による塩基配列の直接的な読みとり、インターカレーションを用いた塩基選択的な光化学反応など、分子認識機能に関する調査・検討を行った。また、最近、DNA中でスタックした塩基対を介した長距離電子移動の可能性が示され、注目を集めるとともに盛んな議論がなされている。本調査では、DNAならびにその類似物における高速な光物理化学現象と分子フォトニクス材料への展開を、光化学、単一分子分光学、などの立場から検討した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1999年 -2000年 
    代表者 : 居城 邦治
     
    本研究の目的は、DNA分子1個のゲノムマッピングを、近接場プローブ顕微鏡を用いた蛍光観察で行うことにある。そのためには、蛍光標識された特異的オリゴヌクレオチドがハイブリッドした単一DNA分子を基板上に引き伸ばして固定化する新手法の開発、また超高感度での蛍光観察のための近接場プローブ顕微鏡へのフォトンカウンティング技術の応用が必要不可欠である。昨年度は、固体基板に引き伸ばして固定化されたDNA1分子に結合した蛍光標識プローブを調べるために、新たにフォトンカウンティングを装備した超高感度近接場プローブ顕微鏡を用いて、引き伸ばされたDNA1分子の蛍光像とDNA自身のトポグラフ像(表面の凹凸)を同時に測定した。本年度はこの手法を用いて単一DNA分子に結合した単一蛍光分子の蛍光像の測定を試みた。具体的には 1)気水界面にて脂質-DNA複合体の単分子膜を形成させ、これをガラス基板に垂直引き上げ法により移し取りDNA試料を作製した。超高感度近接場プローブ顕微鏡により単一DNA分子の長さとDNAの分子量との関係を調べ、DNA一分子が完全に引き延ばされる条件を調べた。(居城邦治ら,高分子加工,50,33(2001)) 2)無蛍光標識二重らせんDNAを引き伸ばしてガラス基板に固定化し、FISH法を行い超高感度近接場プローブ顕微鏡で蛍光プローブの空間的位置を一分子レベルすなわちナノメーターレベルでの計測を試みた。しかし、現有のフォトカウンティングシステムでも単一蛍光分子からの蛍光信号を検出することは困難であった。今後は近接場プローブ顕微鏡の光検出部をより高感度なAPDに交換して引き続き実験を行う予定である。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1998年 -1999年 
    代表者 : 下村 政嗣, 西川 雄大, OLAF Karthau, 居城 邦治, OFFENHAUSSER アンドレアス, KNOLL Wolfga
     
    本研究は、表面プラズモン顕微鏡や走査プローブ顕微鏡を用いた高分子コンプレックスの構造評価に精通した物理学者と、有機合成ならびに分子薄膜の作製を行っている高分子化学者が有機的な連携をとりながら、二分子膜や単分子膜、LB膜のような二次元秩序を有する分子薄膜をマトリックスとして、合成ならびに生体高分子を複合化したナノメーターサイズの高分子コンプレックスを作製し、マイクロメータレベルにいたる幅広い階層にまたがる構造化を行おうとするものである。 本研究では、ナノメーターサイズの高分子コンプレックスとして核酸塩基を有する自己会合単分子膜(SAM)ならびに単分子膜、マイクロメーターサイズの高分子構造体としてハニカム状にパターン化された高分子フィルムを作製し、主として表面プラズモン共鳴法を用いた解析を行うことで、それぞれの構造特性を明らかにした。その結果、相補的な塩基対を形成するSAMとゲスト核酸塩基の組み合わせでプラズモン共鳴の変化が観測された。また、パターン化高分子薄膜の2次元トポグラフィーをプラズモン共鳴のコントラスト像として観察することができた。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1997年 -1998年 
    代表者 : 居城 邦治
     
    本研究の目的は、DNA分子の二次元導電性を測定することである。そのためには、DNA1分子を伸ばして固体基板に固定化する技術、さらに微少領域の二次元導電性を測定できる装置の開発、を行う必要がある。今年度は、1)単分子膜を鋳型とした伸び切り鎖DNAの基板への固定化、2)伸び切り鎖DNAの導電性AFM測定、について研究を行った。 1) 単分子膜を鋳型とした伸び切り鎖DNAの固定化 昨年度は、DNAとカチオン性両親媒性化合物である2C_<18>N+2C_1からなるポリイオンコンプレックスのクロロホルム溶液を、劈開した雲母基板上にキャストすることで、DNA数分子が伸ばされ束になったナノ細線を作製することができた。しかし、このときDNA鎖は両親媒性化合物で覆われているために、新たに開発した導電性AFMでは光導電性を測定することができなかった。そこで裸のDNA分子を固定化するために新たに単分子膜を鋳型とした方法を開発した。DNA水溶液上に2C_<18>N+2C_1を展開して単分子膜を作製した。2Cs_<18>N+2C_1はカチオン性なのでアニオン性のDNAと気水界面で静電的に吸着する。下水相のDNA濃度を希薄にして、単分子膜をガラス基たに垂直浸漬法で移し取ると、伸びたDNA分子が二次元に孤立した状態で固定化されることが、蛍光プローブを用いた蛍光顕微鏡観察でわかった。移し取るときの単分子膜とガラス表面との間の水が流動するときにDNA分子が配向・延伸したものと考えられる。 4) 伸び切り鎖DNAの導電性AFM測定 今回開発した手法によって作製した伸び切り鎖DNA分子の光導電性を、昨年度に開発した導電性AFMを用いて測定した。しかし、DNA分子に沿った光導電性を映像化することができなかった。おそらくDNAに流れる電流量が小さすぎるためと考えられる。現在、導電性AFMの電流測定の感度を上げることを試みている。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1997年 -1998年 
    代表者 : 下村 政嗣, 西川 雄大, KARTHAUS Ola, 居城 邦治
     
    本研究の目的は、二次元に組織化された分子集合体を鋳型として単一分子DNAを配向固定化するとともに、DNAの構造的な特徴である塩基対のスタッキングとそれに伴うパイ電子相互作用による長距離にわたる電子伝達能力を利用した新たな検出原理に基づくDNAのハイブリダイゼーション過程の高感度解析手法を開発し、走査型プローブ顕微鏡下における蛍光分光学測定を行おうとするものである。すでに本申請者らは、二次元分子集合体である単分子膜が規則構造のある荷電表面を形成し、その荷電表面を鋳型として反対電荷を有する高分子電解質が単分子状に静電吸着することを見いだした。DNAはリン酸残基を有するアニオン性高分子なので、カチオン性単分子膜の荷電界面に単分子状に静電吸着すると期待される。界面化学的な手法による単分子膜の相状態の測定、蛍光顕微鏡による水面膜の直接観察、水晶発振子マイクロバランスによる微量重量測定、レーザー分光学的な方法による解析、などによってDNAが単分子膜界面に単一分子的に吸着することを明らかにした。さらに、インターカレーターであるアクリジンオレンジの長鎖誘導体からなる気水界面単分子膜の蛍光寿命が、polyG-polyCを吸着することで著しくみじかくなることをピコ秒蛍光寿命測定装置によって明らかにした。これはグアニン塩基による電子移動消光によるものと考えられる。さらにDNAを単一分子状に分離するために、下水相のDNA濃度を通常の吸着条件の10分の1程度に希釈して単分子膜-DNA複合膜を作製した。蛍光色素(YOYO1)でDNAをラベルしガラス基板上に移し取り、近接場光学顕微鏡で観察したところ、一本のDNA鎖が膜の引き上げ方向に配列していることがわかった。また本研究者は、高分子の希薄溶液をキャストする過程で形成される散逸構造がキャスト基板上に固定化されることで、サブミクロン領域における様々な規則パターンが形成されることを見いだしている。本研究において、DNAの希薄水溶液をキャストすることで幅数百ナノメーター厚さ2ナノメーター、長さ数ミリメーターにいたる規則的に配列したストライプ構造の形成に成功した。さらにパターン化したアルギン酸をマトリックスとして単一DNA分子の配列が可能なことを近接場光学顕微鏡、高感度蛍光顕微鏡観察で明らかにした。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1996年 -1996年 
    代表者 : 居城 邦治
     
    本研究では、DNAの1分子内の塩基配列を調べるために、AFMのプローブ(探針)の先端を塩基対と結合するよう化学修飾して、特異的な水素結合を調べられるような走査型化学力顕微鏡(SCM)を開発することを目的とした。ここでは走査型化学力顕微鏡(SCM)の動作確認を単純化した系で行った。基板表面およびAFMのプローブ表面が親水的もしくは疎水的の場合、プローブに動く力がどうなるのかをフォースカーブにより調べ、そのマッピングを試みた。 1.AFMのプローブをアルカンチオールで修飾するために、プローブ表面をクロム次いで金を蒸着装置にて被覆した。電子顕微鏡観察により10個に2個の割合でプローブ先端まで被覆されることがわかった。 2.金で被覆されたプローブをアルカンチオール溶液に浸し自己組織膜を形成させ、プローブ表面を疎水化した。 3.親水的な基板として劈開した雲母を用い、疎水的な基板としてポリスチレンキャストフィルムを用いた。裸の金表面を持つプローブでは親水性、疎水性基板ではフォースカーブに差はなかった。それに対して疎水化処理したプローブでは異なるフォースカーブを得られた。すなわち、疎水化プローブと疎水表面とは吸着力(化学力)は弱いのに対して、親水表面では強いことがわかった。 4.ポリスチレン微粒子(疎水性)が雲母基板上(親水性)で点在する試料を作製した。これを疎水化プローブで、256×256点で1ポイントごとにフォースカーブを測定し、トポグラフィーおよび吸着力のマッピングに成功した。ポリスチレン微粒子はトポ像では山のように見えるものの、吸着力が雲母表面に比べ弱いことから吸着力のマッピングでは低く見えた。 以上の結果より、プローブと基板表面間の特異的な化学力(吸着力)を測定することで、相補的な水素結合による化学種の検出、すなわちDNAの塩基配列の読み出しが可能であるとが示された。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1995年 -1995年 
    代表者 : 居城 邦治
     
    本研究では、DNAの分子量を測定する方法として、新たに水晶発振子と高感度蛍光顕微鏡を組み合わせたDNA1分子の電気泳動の超微量直接観察法を開発することを目的とした。今年度の実験では、高感度蛍光顕微鏡によるDNAの超微量直接観察法の確立と水晶発振子への電気泳動用電極の加工法の検討を行った。 1.カチオン性界面に固定化されたDNA分子の電気泳動を確認するために、ガラスを基板とした、くし形電極上に、カチオン性脂質ジオクタデシルジメチルアンモニウムブロマイドの気水界面単分子膜1層をラングミュアー-ブロジェット法により累積した。 2.1kbpから100kbpのDNAフラグメントの希薄水溶液から、修飾くし形電極上に静電相互作用によりDNAを固定化した。 3.固定化しDNA孤立分子を、蛍光色素YOYOで染色して、画像処理装置を組み合わせた高感度蛍光顕微鏡で観察した。さらに原子間力顕微鏡による観察も行った。 4.くし形電極に数ボルトから数十ボルトの静電圧を印可して、DNA分子の陽極への移動を観察した。水溶液の塩強度およびpHを種々変化させてもDNA分子の移動は観察されなかった。おそらく、単分子膜表面の4級アンモニウムとDNAのリン酸の結合が強すぎるためと考察される。そのためDNAの界面への結合を弱くする、例えば、単分子膜に非イオン性脂質を添加してカチオン密度を下げる、もしくは4級アンモニウム塩脂質の代わりに1級アミン脂質を使用する、ことが改善策として期待される。 5.水晶発振子上に、電気泳動用電極を金のスパッタリング法により作製を試みた。しかし、このために入手した水晶発振子基板の直径が、1.5cmと小さかったために電気泳動用電極の作製は困難であった。スパッタリング法による電極作製には直径は3cm以上必要であることがわかった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1994年 -1994年 
    代表者 : 居城 邦治
     
    本研究の目的は、水面上にジアルキル型脂質と長鎖アルキル基を持つ一本鎖DNAからなる核酸-脂質複合体を作製すること、および、水相に添加した相補的なDNAとの塩基対形成を、二重鎖DNAに特異的にインターカレートされる色素からの蛍光発光を利用することで高感度に検出しようとすることにある。 1.核酸-脂質複合体として、一本鎖DNAの最小単位の一つである塩基シトシンに長鎖アルキル基を導入したオクタデシルシトシンを新規に合成した。 2.水面上でのインターカレーションを観察するために、色素インターカレーターであるアクリジンオレンジに長鎖アルキル基を導入したオクタデシルアクリジンオレンジを新規に合成した。 3.アデノシン、シチジン、ウリジン、グアノシンをそれぞれ添加した水相上にオクタデシルシトシンの単分子膜を作製して、表面圧-面積曲線を測定した結果、水相にグアノシンが存在するときのみ安定な単分子膜の形成が確認できたことから、水面上での核酸-脂質複合体のシトシンと水相中のグアノシンとの塩基対形成が示唆された。 4.核酸-脂質複合体にオクタデシルアクリジンオレンジを混合させ、水面上での蛍光顕微鏡観察を行ったところ、グアノシン水溶液上では緑色発光が認められ、水面上で形成された塩基対間へのアクリジンオレンジのインターカレーションが確認された。 以上の結果より、インターカレーションによる蛍光発光を利用した水面上での塩基対形成の検出は可能であることがわかった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1991年 -1992年 
    代表者 : 岡畑 恵雄, 居城 邦治
     
    研究目的 本研究の目的は、酵素の表面を脂質膜で被覆することにより酵素機能を改変し、有機溶媒中での不斉エステル合成触媒として利用したり、薄膜化酵素を作ることにある。 研究成果の概要 1)エステラーゼやプロテアーゼなどの酵素水溶液と糖親水基をもつ合成ジアルキル脂質の水分散液を混合して、析出した白色の沈澱を集めて凍結乾燥して酵素ー脂質複合体を得た。 2)得られた酵素ー脂質複合体をイソオクタンなどの有機溶媒に溶かし、これに種々のカルボン酸と不斉アルコールあるいは不斉アミンを加えて室温度で不斉選択エステル化、アミド化反応を行なった。反応は設備備品として初年度に購入したインキュベーターを用いて行なった。その結果、脂質修飾リパーゼは1ーPhenylethanolのRー体を不斉選択的にエステル化することがわかった。 3)酵素の由来や有機溶媒の種類、基質の化学構造を系統的に変化させたところ、酵素の由来により基質選択性や有機溶媒中での安定性が大きく異なることがわかった。すなわち、酵素の由来や用いる有機溶媒の極性を変化させることにより、基質選択性や不斉選択性が制御できることがわかった。 4)酵素としてオキシゲナーゼやヒドロゲナーゼを用いて酵素ー脂質複合体を作製し、有機溶媒に溶かして水面上に展開し、LangmuirーBlodgett(LB)法を用いて白金電極上に1-2層累積した。水溶液中に基質を加えたときの選択的酸化還元反応を電気量から追跡したところ、酸化還元反応の応答性が高いことがわかった。

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  • ソフトマター分子科学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 生命科学院
    キーワード : ナノマテリアル、非共有結合、ホスト－ゲスト化学、自己集合、自己組織化、分子認識、分子マシン、分子インプリント、ドラッグデリバリー
  • ソフトマター分子科学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 生命科学院
    キーワード : 高分子の概念、高分子の分類、高分子の重合反応、高分子のキャラクタリゼーションと分析、高分子材料と工業
  • ソフトマター科学概論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 生命科学院
    キーワード : （生命医薬科学概論） 有機合成化学，天然物化学，神経，免疫，蛋白質，脂質，遺伝子解析，RNA，バイオイメージング解析，薬剤吸収，薬物送達，痛み，立体構造 （生命融合科学概論/ソフトマター科学概論） 生命融合科学，生命情報分子科学，生命物質科学，細胞機能科学，生命機能制御科学，ソフトマター科学，ソフトマター材料科学，ソフトマター生命分子科学，ソフトマター生体物理学，ソフトマター医科学，SDGs （生命システム科学概論） 細胞増殖，細胞極性，細胞分化，形態形成，遺伝子発現，植物免疫，神経回路，動物行動学，能科学，生殖機構，発生，内分泌，ホルモン，オムニバス，現代生命科学，知的財産
  • 生命融合科学概論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 生命科学院
    キーワード : （生命医薬科学概論） 有機合成化学，天然物化学，神経，免疫，蛋白質，脂質，遺伝子解析，RNA，バイオイメージング解析，薬剤吸収，薬物送達，痛み，立体構造 （生命融合科学概論/ソフトマター科学概論） 生命融合科学，生命情報分子科学，生命物質科学，細胞機能科学，生命機能制御科学，ソフトマター科学，ソフトマター材料科学，ソフトマター生命分子科学，ソフトマター生体物理学，ソフトマター医科学，SDGs （生命システム科学概論） 細胞増殖，細胞極性，細胞分化，形態形成，遺伝子発現，植物免疫，神経回路，動物行動学，能科学，生殖機構，発生，内分泌，ホルモン，オムニバス，現代生命科学，知的財産
  • 大学院共通授業科目（一般科目）：自然科学・応用科学
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : ナノ構造、微細加工、光機能性材料、光化学、液晶、分子性物質、導電性、磁性、薄膜、電子顕微鏡、走査型プローブ顕微鏡、ナノワイヤー、二次元電子ガス、物性理論
  • 環境と人間（1単位）
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 最先端技術、ナノテクノロジー、光科学、極微細技術、自己組織化、ナノ材料、半導体、高分子、超分子、フォトニクス、エレクトロニクス、レーザー、物理、化学、量子
  • 環境と人間（1単位）
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 最先端技術、極微細技術、数理、バイオサイエンス、細胞、先端医療、光、レーザー、自己組織化、生物、知能、情報

大学運営

学内役職歴

  • 2021年4月1日 - 2023年3月31日 教育研究評議会評議員
  • 2021年4月1日 - 2023年3月31日 電子科学研究所長
  • 2015年10月1日 - 2017年3月31日 電子科学研究所副所長
  • 2015年4月1日 - 2015年9月30日 電子科学研究所副所長
  • 2017年4月1日 - 2019年3月31日 電子科学研究所副所長
  • 2019年4月1日 - 2021年3月31日 電子科学研究所副所長
  • 2023年4月1日 - 2025年3月31日 電子科学研究所長

委員歴

  • 2014年07月 - 現在   特定非営利活動法人バイオミメティクス推進協議会 理事
  • 2012年10月 - 現在   ISO/TC266バイオミメティクス国内審議委員会 委員
  • 2004年04月 - 現在   Asian Conference on Nanoscience & Nanotechnology (AsiaNANO), Steering Committee
  • 2004年04月 - 現在   社団法人高分子学会北海道支部幹事
  • 2002年04月 - 現在   社団法人高分子学会バイオ・高分子研究会運営委員
  • 2016年04月 - 2018年03月   バイオミメティクス研究会 第33期運営委員
  • 2016年03月 - 2018年03月   日本化学会 生体機能関連化学・バイオテクノロジーディビジョン 幹事
  • 2015年05月 - 2017年04月   一般社団法人電気学会「新しい原子分子組織化物質・材料創出に向けた 光・量子ビーム応用技術調査専門委員会 委員
  • 2016年03月 - 2017年02月   日本化学会 生体機能関連化学部会 幹事
  • 2014年04月 - 2016年03月   独立行政法人科学技術振興機構「戦略的創造研究推進事業」領域アドバイザー
  • 2014年07月 - 2015年05月   第64回高分子学会年次大会運営委員
  • 2012年06月 - 2014年05月   社団法人高分子学会北海道支部長
  • 2012年05月 - 2014年05月   社団法人高分子学会第31期理事
  • 2012年05月 - 2014年05月   社団法人高分子学会高分子編集委員会支部委員

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