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Sazaki Gen

Institute of Low Temperature Science　Frontier Ice and Snow ScienceProfessor

Researcher basic information

■ Degree
  • Doctor of Engineering, Osaka City University
  • Master of Engineering, Osaka City University
  • Bachelor of Engineering, Osaka City University
■ URL
researchmap URLホームページURL■ Various IDs
Researcher number
  • 60261509
ORCID IDResearcher ID
  • D-8035-2012
J-Global ID■ Research Keywords and Fields
Research Keyword
  • crystal growth, ice, protein, development of advanced optical microscopy
  • Crystal Growth
Research Field
  • Natural Science, Biophysics, chemical physics and soft matter physics
  • Nanotechnology/Materials, Thin film/surface and interfacial physical properties
  • Nanotechnology/Materials, Crystal engineering
  • Nanotechnology/Materials, Applied physical properties
■ Educational Organization

Career

■ Career
Career
  • Jul. 2014 - Sep. 2014
    Chinese Academy of Science, National Microgravity Laboratory, Institute of Mechanics, Visiting Professor
  • Aug. 2007 - Mar. 2014
    - Specially Appointed Professor,Dept. Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University
  • 2007 - Mar. 2014
    - 大阪大学大学院工学研究科電気電子情報工学専攻 特任教授
  • 2008 - 2012
    科学技術振興機構さきがけ研究者 さきがけ研究者
  • 2008 - 2012
    Hokkaido University, Institute of Low Temperature Science
  • 2008 - 2012
    Researcher on Precursory Research for Embryonic Science and Technology (PRESTO),Japan Science and Technology Agency
  • 2012
    - 北海道大学低温科学研究所 教授
  • 2012
    - Professor,Institute of Low Temperature Science, Hokkaido University
  • 2007 - 2008
    スペイン科学研究高等評議会，アンダルシア地球科学研究所，結晶学研究室 契約研究者
  • 2007 - 2008
    Investigado Contrato,Laboratorio de Estudios Cristalograficos, Instituto Andaluz de Ciencias de la Tierra, Consejo Superior de Investigaciones Cientificas
  • 2001 - 2007
    Tohoku University, Institute for Materials Research
  • 2001 - 2007
    Lecturer,Institute for Materials Research, Tohoku University
  • 2004 - 2006
    Tohoku University, Center for Interdisciplinary Research
  • 2004 - 2006
    Project Leader,Center for Interdisciplinary Research, Tohoku University
  • 2001 - 2004
    Tohoku University, Center for Interdisciplinary Research
  • 2001 - 2004
    Program Leader,Center for Interdisciplinary Research, Tohoku University
  • 1994 - 2001
    Tohoku University, Institute for Materials Research
  • 1994 - 2001
    Research Associate,Institute for Materials Research, Tohoku University
Educational Background
  • 1994, Osaka City University, 工学研究科, 応用化学科, Japan
  • 1994, Osaka City University, Graduate School, Division of Engineering, Department of Applied Chemistry
  • 1991, Osaka City University, 工学研究科, Graduate School of Engineering, Japan
  • 1991, Osaka City University, Graduate School, Division of Engineering
  • 1989, Osaka City University, Faculty of Engineering, 応用化学科, Japan
  • 1989, Osaka City University, Faculty of Engineering, Department of Applied Chemistry
Committee Memberships
  • Aug. 2023 - Present
    International Organization for Crystal Growth, Vice president
  • Apr. 2022 - Present
    日本結晶成長学会, 学会誌編集委員長
  • Apr. 2016 - Jul. 2023
    日本結晶成長学会, 国際交流委員会担当理事, Society
  • Apr. 2019 - Mar. 2022
    日本結晶成長学会, 副会長, Society
  • Aug. 2016 - Feb. 2020
    Journal of Crystal Growth, Associate Editor, Others
  • Apr. 2018 - Mar. 2019
    日本物理学会, 領域９代表, Society
  • Apr. 2017 - Mar. 2018
    日本物理学会, 領域９副代表, Society
  • Apr. 2014 - Mar. 2017
    日本物理学会, 代議員（領域９）, Society
  • Apr. 2013 - Mar. 2016
    日本結晶成長学会, 総務委員会担当理事, Society
  • Oct. 2015 - Oct. 2015
    日本結晶成長学会, 第45回結晶成長国内会議現地実行委員長, Society
  • 2010 - 2012
    日本結晶成長学会, 理事（編集委員会）, Society
  • 2008 - 2009
    日本物理学会, 領域９世話人（結晶成長）, Society
  • 2005 - 2007
    日本マイクログラビティ応用学会, 理事, Society
  • 2005 - 2007
    日本結晶成長学会, 理事, Society
  • 2004 - 2007
    日本結晶成長学会, バイオ・有機マテリアル分科会，代表幹事, Society
  • 2000 - 2006
    日本結晶成長学会, 編集委員, Society
  • 2002 - 2004
    日本結晶成長学会, 評議員, Society
  • 2000
    日本マイクログラビティ応用学会, 宇宙実験計画立案, アドバイザリー委員会委員（タンパク質結晶成長）, Society
  • 1997 - 1998
    日本物理学会, 結晶成長分科会世話人, Society

Research activity information

■ Awards
  • Nov. 2024, Japanese Association for Crystal Growth, Contribution Awards for Japanese Association for Crystal Growth
    The Chair of the 45th Japanese Conference for Crystal Growth (October 19-21, 2015) and The Editor-in-Chief of Journal of the Japanese Association for Crystal Growth (2022-2024)
    Gen Sazaki
  • Nov. 2009, Japanese Association for Crystal Growth, The 26th Best Paper Award
    Development of advanced optical microscopy and elucidation of growth mechanisms of protein crystals at the molecular level
    SAZAKI Gen
  • Oct. 2003, The Japan Society of Microgravity Application, The 1st Young Scientist Award
    Effects of external fields on protein crystallization
    SAZAKI Gen
■ Papers
■ Other Activities and Achievements
■ Books and other publications
■ Syllabus
  • 大学院共通授業科目（教育プログラム）：南極学, 2024年, 修士課程, 大学院共通科目
  • 宇宙物質相転移科学特論, 2024年, 修士課程, 理学院
  • 宇宙理学入門, 2024年, 修士課程, 理学院
  • 環境と人間, 2024年, 学士課程, 全学教育
■ Affiliated academic society
  • 応用物理学会
  • 日本マイクログラビティ応用学会
  • 日本物理学会
  • 日本結晶成長学会
  • The Japan Society of Applied Physics
  • The Japan Society of Microgravity Application
  • The Physical Society of Japan
  • Japanese Association of Crystal Growth
■ Research Themes
  • Studies on the correlation between structural changes in the outermost surface layers of ice crystals and their growth kinetics at ultra-high temperatures
    Grants-in-Aid for Scientific Research
    01 Apr. 2023 - 31 Mar. 2026
    佐崎 元; 長嶋 剣; 村田 憲一郎
    令和5(2023)年度には，次の３点の開発および研究を行った．
    １）低温観察チャンバーシステムの作製：-20~0°Cの温度領域で±0.05°Cの温度精度で氷結晶の温度を制御できる観察チャンバーシステム（既に１台現有）を新たに１台作製した．
    ２）極低温観察チャンバーシステムの作製：-140~-20°Cの極めて幅広い温度領域で±0.1°Cの温度精度で氷結晶の温度を制御できる観察チャンバーシステムを全く新たに設計・開発した．
    (1)開発第1号機：ロータリー式真空ポンプによる減圧を利用して液体窒素を送液することで，無酸素銅製のステージを冷却した．また，銅ステージにヒーターを取り付け，液体窒素の送液量とヒーターの加熱量を精密に制御することで温度を制御した．しかし，減圧された配管内部での液体窒素の昇華に伴い，温度が低下し液体窒素が固化する現象が頻発した．これを防ぐために，配管に外部から十分な量の熱が常に伝わる構造とした．その結果，本チャンバーは-90°Cまで温度を下げた状態で，チャンバー内部に約10°Cの温度分布ができてしまうことがわかり，開発を断念した．ステージが外部と比較的多く熱接触していたことが，温度分布発生の原因であると考えられた．
    (2)開発第２号機：そこで，次にステージと外部との接触面積を，力学的な強度が確保できる限りにおいて最小にすることで温度分布の改善を試みた．その結果，温度を-140°Cまで低下させることに成功したとともに，-140°C時におけるステージ内の温度分布を0.8°C以内に抑え，ほぼ均一な温度分布を実現することにも成功した．
    ３）１）２）で作製した両観察チャンバー中で氷結晶を成長させ，氷結晶表面上の単位ステップをレーザー共焦点微分干渉顕微鏡を用いてその場観察することにも成功した．今後，様々な温度領域で単位ステップの形状や成長ダイナミクスを観察・計量する予定である．
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K26555
  • Presumption of statistical mechanical state distribution of 3D protein structure in solution states by crystallization
    Grants-in-Aid for Scientific Research
    01 Apr. 2021 - 31 Mar. 2024
    鈴木 良尚; 佐藤 正英; 佐崎 元
    「研究実施計画」において、初年度はニワトリ卵白リゾチーム（HEWL）斜方晶系結晶を使って、NaCl濃度を細かく刻んで結晶化し、Na+サイト周辺で、変化する電子密度のNaCl濃度依存性を明らかにする予定であったが、塩濃度の変化による構造変化よりも、温度変化による構造変化の効果が圧倒的に大きいという予定外の事実が判明したため、急遽確認作業に追われた。2022年度に実験を予定していて、予備実験を実施していたグルコースイソメラーゼ（GI）について、沈殿剤フリーの遠心濃縮によって得られた結晶を、SPring-8において90 Kで構造解析して得られた構造と、Protein Data Bank（PDB）に登録されている、硫酸アンモニウムによる塩析で得られた結晶による1XIBという構造を比較したところ、構成分子の平均二乗変位（RMSD）が0.234Åであった。それに対して、研究室線源で100 Kで構造解析した沈殿剤フリー結晶で得られた構造のとの間のRMSD は 0.075Åであったため、塩濃度による違いが明らかに出たと思っていた。ところが、念のため、硫酸アンモニウムの塩析結晶における構造の一つである4A8Iと比較したところ、RMSD = 0.072Åとなり、塩濃度による違いはなかった。4A8Iは100 Kで構造解析していたため、温度変化の方がはるかに大きかった。これらの結果から、再現性の良い、常温における沈殿剤フリーのタンパク質結晶構造解析法が必要となり、その過程で、蒸発によるタンパク質の新規結晶化法を開発できたためCrystals誌に論文化した。
    また、タンパク質分子の単純化モデルとしてパッチ粒子の相互作用と結晶構造の相関について、シミュレーションした結果をScientific reports, Japanese Journal of Applied Physics誌に投稿した。
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), The University of Tokushima, 21K04908
  • Exploring general nature of interfacial melting on ice crystals: in situ approach by optical microscopy
    Grants-in-Aid for Scientific Research
    01 Apr. 2021 - 31 Mar. 2024
    村田 憲一郎; 佐崎 元
    令和3年度は，主に①正立型レーザー共焦点微分干渉顕微鏡（LCM-DIM）システムの構築とLCM-DIMによる一分子段差の検出，および②全反射照明を組み込んだ氷成長観察チャンバー（正立用）の開発に取り組んだ．以下にその概要を記す．


    ①正立型LCM-DIMの構築後，標準試料として石膏とシリコンカーバイトの結晶表面を観察し，両サンプルにおいて一分子段差（それぞれ，0.76nm，0.5nm）の観察に成功した．当初の計画通り，既存のLCM-DIM（オリンパス社製）と同等の高さ分解能を達成しつつ，時間分解能を上回る性能を得られた．加えて，Zeiss社の独自技術である円偏光微分干渉顕微鏡（C-DIC）の共焦点化にも取り組んだ．通常の微分干渉顕微鏡は，段差コントラストに異方性を持ち，特定方向のコントラストが落ちることが知られている．従来のLCM-DIMにおいても同様の弱点があり，コントラストの弱い単位ステップのダイナミクスをその場観察する上で弊害となり得る．一方，C-DICでは円偏光を用いることで，コントラストの異方性を任意の方向に制御することが可能である．今回の研究により，C-DICの共焦点化に成功し，Åオーダーの高さ分解能を維持しつつコントラストの異方性を任意に調整することが可能となった．


    ②倒立型顕微鏡用にプロトタイプとして作成していた全反射照明系氷成長観察チャンバーを改良し，正立型LCM-DIMで使用できるようにした．これにより，次年度にシングルフォトン検出器を導入次第，直ちに微粒子からのエバネッセント光の散乱を観察できる段階に入った．
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 21H01824
  • 多結晶氷の表面融解機構の解明
    平成31年度科学研究費補助金，基盤研究(B)
    Apr. 2019 - Mar. 2022
    佐﨑 元
    Principal investigator, Competitive research funding
  • Crystallization and crystallography of proteins at in vivo salt concentrations
    Grants-in-Aid for Scientific Research
    01 Apr. 2018 - 31 Mar. 2021
    SUZUKI Yoshihisa
    We have clarified significant structure changes in three-dimensional structure of protein molecules in crystals from different growth conditions. We studied effects of the difference in precipitant condition on the structure, and published papers on the result. In addition, in dilute precipitant conditions, liquid-liquid phase separation frequently occurred during centrifugal concentration of solutions. In the dense liquid phase after the separation, nucleation and growth of crystals occurred very rapidly. Growth rates of obtained crystals in the dense liquid were at least an order of magnitude faster than those in conventional salting-out conditions. In spite of such very rapid processes, maximum resolution limits of obtained crystals were very high (less than 0.1 nm, for instance).
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), The University of Tokushima, 18K04960
  • Communication of insects through body surface lipids: proposal of a new mechanism employing mechanoreceptors
    Grants-in-Aid for Scientific Research
    29 Jun. 2018 - 31 Mar. 2020
    Kaneko Fumitoshi
    The outermost layer of insects is a very thin layer (0.1-1 μm) of hydrocarbons. In addition to their barrier functions to adopt the environment, the body lipid is used for the communication between insects. Although it is the common view that insects communicate each other by detecting the difference in the chemical composition of the body lipid by using chemical sensors on antennae, we have postulated the possibility that insects also detect the difference in the physical properties by mechanical sensors.
    To inspect the validity of this postulation, the body lipid of the field cricket, which shows a gender gap in composition, has been studied with respect to the structure and properties at in-situ on body surfaces by using atomic force microscopy (AFM) and other methods. The friction force detected by AFM is clearly different between male, female, and degreased body surfaces, which strongly suggests that such differences are detected by the mechanical sensor systems of insects.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Osaka University, 18K19214
  • Anisotropic function of antifreeze protein for ice crystal growth - To elucidate growth promotion and inhibition mechanism
    Grants-in-Aid for Scientific Research
    01 Apr. 2014 - 31 Mar. 2018
    FURUKAWA Yoshinori
    Growth experiments of an ice crystal in a supercooled solution of antifreeze protein were carried out and separately measured the growth rates for the basal and prism faces. We clarified that the growth of basal faces was enhanced by the effect of antifreeze protein, while the growth of prism faces was suppressed. It means that the effects of antifreeze proteins for ice crystal growth were different for every crystallographic faces.
    The growth promotion of basal face was explained by a new model that the adsorbed antifreeze protein molecules on the edges of growth steps may work as the new sources to generate new growth steps on the basal faces. We clarified that the mechanism for the freezing inhibition of living organisms under the sub-zero temperature environments was compatibly explained on the basis of the anisotropic functions of antifreeze proteins for ice crystal growth.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 26287095
  • 不凍タンパク質が示す相互作用の解明：拡散・吸着ダイナミクスの蛍光１分子計測
    平成28年度科学研究費補助金，挑戦的萌芽研究
    Apr. 2016 - Mar. 2018
    佐﨑 元
    Principal investigator, Competitive research funding
  • 結晶表面上の化学反応を可視化する：氷表面上での酸性ガスの吸着・融解反応の解明
    平成27年度科学研究費補助金，基盤研究(A)
    Apr. 2015 - Mar. 2018
    佐﨑 元
    Principal investigator, Competitive research funding
  • Melt-like growth of protein crystals
    Grants-in-Aid for Scientific Research
    01 Apr. 2014 - 31 Mar. 2017
    Suzuki Yoshihisa
    Salt-free protein crystallization method with centrifugal concentration apparatus has been developed. With this method, nucleation of hen egg-white lysozyme (HEWL) crystals occurs in hyper-concentrated liquid phase obtained by liquid-liquid phase separation during centrifugal concentration processes. We could successfully observed molecular steps on the obtained crystal surface. Three-dimensional structure of lysozyme molecule obtained in this method is significantly different from that obtained by normal salting-out method.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), The University of Tokushima, 26390054
  • Development of label-free and quantitative imaging of cell adhesion
    Grants-in-Aid for Scientific Research
    01 Apr. 2014 - 31 Mar. 2016
    YOSHIKAWA Hiroshi; SAZAKI Gen
    In this work, a high-contrast and quantitative imaging method of cell adhesion has been developed by improving instruments and analysis of optical interferometry. In addition, the new method was applied to the study of the quantitative correlation between adhesion and functions of various cells. In particular, the method provided the first quantitative insights into the correlation between adhesion and metastatic ability of cancer cells, which clearly shows the potential of this method for the applications to label-free screening of cell adhesion.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Saitama University, 26650046
  • Computer Simulation on Creative Development of Fusion Materials through Molecular Control
    Grants-in-Aid for Scientific Research
    01 Apr. 2010 - 31 Mar. 2015
    NADA Hiroki; SAZAKI Gen
    In this study, attention was paid to the fact that the crystallization of minerals in organisms (biomineralization) is precisely controlled by additives, such as proteins, peptides and polymers. For several topics concerning the crystallization control of calcium carbonate, which is a representative mineral in biomineralization, we elucidated the mechanism of the crystallization control by additives using a computer simulation method at the molecular scale. An important conclusion derived from this study is that water at the crystal surface is crucial in the crystallization control. This study contributed to the creative development of fusion materials by providing fundamental knowledge obtained in this study for experimental groups concerning the design of functional molecules and materials synthesis in the fusion materials project.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), National Institute of Advanced Industrial Science and Technology, 22107004
  • 高分解光学観察による氷結晶表面での疑似液体層の動的挙動の解明
    平成23年度科学研究費補助金，基盤研究(A)
    Apr. 2011 - Mar. 2015
    佐﨑 元
    Principal investigator, Competitive research funding
  • 水−氷（融液−結晶）界面の分子レベル直接観察：超高感度位相差顕微鏡の開発
    平成24年度科学研究費補助金，挑戦的萌芽研究
    Apr. 2012 - Mar. 2014
    佐﨑 元
    Principal investigator, Competitive research funding
  • Static and kinetic effect of impurities on instability of shape of crystal
    Grants-in-Aid for Scientific Research
    2011 - 2013
    SATO Masahide; SAZAKI Gen; SUZUKI Yoshihisa; KATSUNO Hiroyasu
    We studied effects of impurities attached to a surface from theoretical and experimental points of view. We showed that increasing of the diameter of 2-dimensional island-like crystal is caused by impurities. Carrying out Monte Carlo simulation, we studied motions of steps on a vicinal face during bunching induced by impurities. We also showed the possiblity of increasing the diffusion coefficient of 2-dimensional island like crystal due to impurities.
    We tried to study the effect of impurities in solid on behaviors of 2-dimensional island-like crystal, which is caused by long range interaction,
    and to form an alloy of 2 types of proteins. We cannnot obtain clear conclusioins about The studies, so we continue studying these themes.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Kanazawa University, 23540444
  • 不凍タンパク質作用発現機構の解明を目指したその場光観察
    戦略的創造研究推進事業さきがけ
    Oct. 2008 - Mar. 2012
    佐﨑 元
    科学技術振興機構, Principal investigator, Competitive research funding
  • 分子レベルその場観察によるタンパク質結晶へのマイクロ欠陥取り込み機構の解明
    平成18年度科学研究費補助金，基盤研究(B)
    Apr. 2006 - Mar. 2009
    佐﨑 元
    Principal investigator, Competitive research funding
  • Anisotropic dynamics of ice growth promotion and its self-oscillation induced by the interfacial adsorption of biological macro molecules
    Grants-in-Aid for Scientific Research
    2006 - 2009
    FURUKAWA Yoshinori; SAZAKI Gen; KATAGIRI Chihiro; YOKOYAMA Etsuro; NADA Hiroki; KANEKO Fumitoshi
    Experimental and theoretical studies of antifreeze proteins, which have the special function to prevent the freezing of living organisms under the subzero environment, were carried out. Direct evidence for the relation between the adsorption of proteins on the ice interfaces and the prohibition of crystal growth was first demonstrated directly, and it was made clear that the protein molecule adsorption proceeded in two stages depending on the conformation change of protein molecules. This adsorption mode was completely new and called as "two-step reversible adsorption". This adsorption model also explained the growth promotion of basal planes of ice and the self oscillations of growth rates.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 18204036
  • X線導波路現象を利用した有機薄膜高次構造のリアルタイム観測
    科学研究費助成事業
    2006 - 2008
    林 好一; 佐崎 元
    放射光実験施設Photon FactoryのBL3Cにおいて、白色X線を用いたX線導波路の実験を行った。ここでは、Si/PMMA/Siの多層膜を作製し、白色X線を薄膜試料に照射し、薄膜端面から放出されるX線をエネルギー分散型X線検出器によって観測した。PMMA層においてX線の共鳴現象を起こすため、薄膜端面からのX線は分光され、TE(transverse electric)0、TE1、TE2の3つの共鳴モードのピークを観測することができた。また、これらのピークのエネルギー値は、薄膜の高次構造に大きく影響されるため、エネルギー値を解析することによって、薄膜の膜厚、密度を精度よく決定することができる。さらに、本年度は、リアルタイムで、X線導波路現象によるX線スペクトルの変化を観測することによって、薄膜の高次構造の素早い時間変化を追うことを試みた。一つのスペクトルの測定時間は10秒である。上記試料に対し、強力な放射光白色X線を照射することにより、即座に試料の変性が開始され、約200秒後に短時間で、その変化が完了することがわかった。ここでは、特に、TE2のピークのシフト量がTEOのものより大きいことが特徴的であった。このことより、PMMA層の密度は大きく変化せず、膜厚のみが変性したことが示された。標準のX線反射率測定装置も用い、詳細に解析した結果、元々膜厚100nm程度であったものが、約10%程度小さくなり90nm程度になることが観測された。今回の実験から、白色X線を用いたX線導波路現象による分光X線の観測が、薄膜高次構造のリアルタイム観測に非常に有望であることが判明した。
    日本学術振興会, 萌芽研究, 東北大学, 18656003
  • Crystal Growth of Snow and Ice
    2008
    Competitive research funding
  • タンパク質結晶-溶液界面におけるタンパク質１分子の吸着・脱離・拡散ダイナミクス
    平成17年度科学研究費補助金，特定領域研究（公募研究）
    Apr. 2005 - Mar. 2007
    佐﨑 元
    Principal investigator, Competitive research funding
  • Study of atomistic diffusion, nucleation and cluster formation process of atoms and molecules
    Grants-in-Aid for Scientific Research
    2005 - 2007
    SUTO Shozo; SAZAKI Gen; YAMADA Taro; HAYAKAWA Yoshinori
    Recently, it is possible to observe atomistic motion of single atoms or single molecules on solid surfaces due to the development of surface probe microscopy, in particular scanning tunneling microscopy (STM). First goal of this study is to understand a cluster formation process from atomistic diffusion of single atoms, just after deposition up to 8 hours. We observed the atomistic motion of Ag atoms on a Si(111)7x7 surface and the formation process of (Ag)n clusters in a 7x7 surface potentials. It is found that the diffusion is cooperative where the hopping rates depend on the nearest neighbor sites. We also measured the tunneling spectroscopy and found that the n=5 and 6 clusters have a specific electronic energy level: Second goal is to investigate the weakest interaction between substrate and the adsorbate atoms or molecules. We observed two -epitaxial structures of pentacene polycrystalline thin film crystals on a hydrogen-terminated Si(111) surface and commensurabilites. Furthermore, we observed the step-induced anisotropic growth of pentacene thin film crystals on a hydrogen-terminated Si(111) surface. In the early stage of this study, we proposed the process for ultra-clean and atomically controlled hydrogen-terminated Si(111)-(1x1) Surface and it is revealed by high resolution electron energy loss spectroscopy, atomic force microscopy and scanning tunneling microscopy. We also propose the deuterium terminated Si(111) surface and observed the surface phonons. Third goal is to investigate the strong interaction between substrate and the adsorbate atoms. Formation process and surface structure of platinum silicide thin layers was studied using STM.
    Now, we are able to manipulate the single atom or molecule and, then, we try to estimate the cluster size and the electronic structure. Our final goal is to understand the cluster formation process, surface reaction and to form an electronic devices in the atomic scale.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tohoku University, 17340091
  • 蛍光顕微法を用いた有機半導体薄膜結晶粒間の位相欠陥イメージング
    平成16年度科学研究費補助金，萌芽研究
    Apr. 2004 - Mar. 2006
    佐﨑 元
    Principal investigator, Competitive research funding
  • タンパク質結晶成長素過程の１分子その場観察による格子欠陥取り込み機構の解明
    平成16年度科学研究費補助金，基盤研究(B)
    Apr. 2004 - Mar. 2006
    佐﨑 元
    Principal investigator, Competitive research funding
  • 環境型バイオデバイス創製のための有機・無機ヘテロエピタキシャル結晶成長技術の開発
    平成13年度研究助成
    Apr. 2001 - Mar. 2002
    佐﨑 元
    財団法人稲盛財団, Principal investigator, Competitive research funding
  • 強磁場下でのタンパク質結晶周囲の濃度場観察
    平成12年度科学研究費補助金，奨励研究(A)
    Apr. 2000 - Mar. 2002
    佐﨑 元
    Principal investigator, Competitive research funding
  • Research on functional electronic devices based on straind-Si on SiGe alloy substrates
    Grants-in-Aid for Scientific Research
    2001 - 2002
    USAMI Noritaka; KOH Shinji; NAKAGAWA Kiyokazu; NAKAJIMA Kazuo; UJIHARA Toru; SAZAKI Gen
    The purpose of this research is to realize strain-controlled Si-based heterostructures with superior electronic properties on homemade SiGe substrates wish uniform Ge composition.
    Firstly, we tried to develop a feedback control system of the crystal-melt interface position and temperature based on in-situ monitoring system. Automatic recognition of the interface position was successful by binarization and differentiation of the CCD image. By utilizing newly developed system, we succeeded in growing SiGe with uniform composition. To improve the crystal quality, we systematically changed the temperature gradient at around the crystal-melt interface. At a result, systematic decrease of the line-width of the X-ray rocking curve and increase of the intensity were confirmed presumably due to the suppression of constitutional supercooling. In addition, crystal quality was found to be strongly dependent on the orientation of the seed crystal.
    On homemade SiGe, modulation doped structure with strained-Ge channel was grown by molecular beam epitaxy. Although improved carrier mobility was not achieved, controllability of strain was confiemed.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tohoku University, 13555086
  • 過冷炉度を制御した融液成長法による太陽電池用Si多結晶の大粒径化と高効率化
    科学研究費助成事業
    2001 - 2002
    中嶋 一雄; 宇治原 徹; 佐崎 元; 宇佐美 徳隆; 北原 邦紀; 藤原 航三
    研究目的:多結晶シリコンは実用太陽電池材料として利用されているが単結晶材料に比べてエネルギー変換効率が低い。その原因として、結晶粒界や転位や不純物など結晶欠陥の影響が考えられている。このような結晶欠陥は融液成長時に導入されるが、その制御方法は確立されていない。本研究では融液成長時の過冷度を精密に制御して成長を行い過冷度や潜熱と結晶欠陥および結晶粒径の相関を解明する。
    本年度の実績:本年度は融液成長過程および成長温度を同時に観察できる装置を設計・導入した。本装置は観察窓付きの一方向成長特殊小型炉と赤外線放射温度計を組み合わせた装置である。小型炉は高真空に引いた後アルゴンガス置換でき、冷却速度および炉内温度を精密制御できる。また、冷却ガスによる強制冷却機構と種付け機構を有する。さらに示差熱検出機構を有している。放射型温度計は顕微機構を有し、赤外と同時に高速度CCDカメラで可視像を観察できるため、成長過程と温度を同時に測定できる。試料サイズは10×15×5mm^3程度であり、成長後組織解析を行うのに十分な大きさである。
    予備実験としてレーザー顕微鏡とイメージ炉を組み合わせた装置を用いてシリコンの融液成長過程をその場観察した。φ3×2mm^3の試料を融解後さまざまな速度で冷却し界面の形態および成長速度を実測した。3K/minで冷却した試料の成長界面はplanar界面であったが25K/min、40K/min、および45k/min冷却した試料ではfacet界面であった。定常状態における成長速度はplaner界面ではV【less than or equal】30μmであったがfacet界面では150μm【less than or equal】V【less than or equal】390μmであった。また非定常状態ではfacet面の消滅過程も観察された。非定常状態ではさまざまなfacet面が形成されたが(111)facet以外の面は消滅し、定常状態では(111)facetのみ形成した。また、赤外線カメラを用いてfacet界面前方の温度測定を行った。界面前方の過冷度はおよそ7度であった。
    日本学術振興会, 基盤研究(A), 東北大学, 13305002
  • Development of advanced optical microscopy
    2002
    Competitive research funding
  • 磁場を利用した微小重力下でのタンパク質の結晶化
    平成10年度宇宙環境利用に関する公募地上研究 フェーズIA
    Oct. 1998 - Mar. 2001
    佐﨑 元
    財団法人日本宇宙フォーラム, Principal investigator, Competitive research funding
  • 磁場中の溶液挙動の解明とそれを用いたタンパク質の良質結晶育成
    黎明研究
    Apr. 2000 - Feb. 2001
    佐﨑 元
    日本原子力研究所, Principal investigator, Competitive research funding
  • 磁場によるタンパク質の高品位結晶育成
    平成10年度科学研究費補助金，基盤研究(B)
    Apr. 1998 - Mar. 2000
    佐﨑 元
    Principal investigator, Competitive research funding
  • Research on spatially and temporally resolved spectroscopy of semiconductor quantum structures by using ulta small probe light
    Grants-in-Aid for Scientific Research
    1999 - 2000
    USAMI Noritaka; UJIHARA Toru; SAZAKI Gen; NAKAJIMA Kazuo; SHIRAKI Yasuhiro
    In this project, we have tried to establish spectroscopic technique to evaluate microscopic interface roughness, and to characterize inherent optical properties of quantum structures without being affected by structural fluctuations. As a technique, we exploited to combine local probe spectroscopy to use objective lens for microscope and lithography technique to fabricate small window on top of the sample, leading to improved spatial resolution.
    We selected quantum structures made from compound semiconductors, which are studied to improve electrical and optical device performance. By reducing the feature sizes such as quantum wires and quantum dots, the impact of the size fluctuations on the properties becomes significant. This explains why we selected the quantum structures.
    We found that localized excitons trapped by some microscopic potential fluctuations in InGaAs/GaAs quantum wells, which are not detected by macroscopic photoluminescence, can be detected by our technique. By measuring growth teroperature dependence, we clarified that the increase of the growth temperature lead to the deterioration of the interface abruptness due to the In surface segregations, however, the interface roughness is improved compared to the sample grown at lower temperatures. In addition, we succeeded in observing charged excitons in quantum dots and controlling the charged states by applying electric field to modulation-doped quantum dots.
    Furthermore, we tried to create novel quantum structures to insert ultra thin film as a localized center for electrons, and succeeded in improving drastically improve the luminescence efficiency of indirect semiconductors, and we found that stacking of quantum dots greatly modify the growth mode. As a next step, we will apply our spectroscopic technique to these quantum structures and clarify their microscopic structures and mechanisms for improved luminescence efficiency.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), 11650008
  • Development of multicomponent bulk single crystal with uniform composition by the multicomponent zone-melting method
    Grants-in-Aid for Scientific Research
    1999 - 2000
    NAKAJIMA Kazuo; UJIHARA Toru; SAZAKI Gen; USAMI Noritaka; ISHIKAWA Hiroshi; MIYASHITA Satoru
    In this project, we have tried to establish a technology to grow multicomponent semiconductor bulk crystals with uniform composition, which are expected to lead to the creation of new functional heterostructures by greatly widening the choices of lattice constant and band gap of semiconductor substrates. By utilizing the technology, we have grown SiGe bulk crystals.
    In Fy1999, we designed new growth system equipped with an in-situ monitoring system of the position and the temperature at the growth interface. The system includes a quartz slit which allows an optical access, and a CCD camera to observe the position of the interface, and a thermoviewer to obtain the temperature distribution. In addition, the information can be used to control the pulling rate of the ampoule for the crystal growth. Therefore, precise control of the growth temperature is possible.
    The starting materials for the SiGe bulk crystal are a Si single crystal as a source, polycrystalline Ge, and Ge (100) single crystal as a seed. By putting the ampoule in an appropriate temperature gradient, polycrystalline Ge and a top part of Ge single crystal are melted to prepare a growth melt. Then, Si dissolves into Ge melt and Si atoms are carried to the interface, mainly by diffusion originating from the concentration gradient, and also by possible influence of convection. Consequently, the supercooling is formed around the growth interface and a driving force for the growth of SiGe crystal is established.
    By monitoring the interface position during the growth with fixed ampoule, we obtained the growth rate of the crystal. By pulling down the ampoule balanced with the growth rate, we succeeded in growing SiGe with fixed interface position. The pulling down the ampoule was confirmed not to affect the temperature distribution. In other words, SiGe was grown under fixed growth temperature. In fact, EDX analysis clarified that the composition of the crystal is uniform over 20mm.
    As a next step, we will apply this technique to various material system, and perform epitaxial growth on our original substrates to create new functional heterostructures.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A)., Tohoku University, 11305001
  • 磁場によるタンパク質の高品位単結晶育成
    黎明研究
    Apr. 1998 - Feb. 1999
    佐﨑 元
    日本原子力研究所, Principal investigator, Competitive research funding
  • タンパク質分子の等電点の新測定法と電極界面凝集化過程のその場観察
    科学研究費助成事業
    1999 - 1999
    宮下 哲; ダービン・ステファン デュエン; 佐ざき 元; 中嶋 一雄
    タンパク質のような両性イオンの溶液内での挙動を理解するとき、等電点は重要な物理量である。特にタンパク質の吸着・凝集・結晶核形成では、凝集力を評価する鍵になる。タンパク質分子の基板への吸着は、分子の等電点・基板の電位・溶液水素イオン濃度と密接に関係しているはずである。本研究は、電気化学原子間力顕微鏡を使い、タンパク質溶液内に置いた導電性の基板の観察を行い、電位変化に対する像の様子から等電点を決める新手法の開発を目指した。
    研究では、等電点の分かっている卵白リゾチーム(等電点=11)水溶液を使い、この中に置いた高配向グラファイト基板上へのタンパク質分子の吸着の様子を観察した。リゾチームの等電点は11であるため、溶液の水素イオン濃度が11よりも大きいと分子は負に帯電し、逆に11よりも小さいと正に帯電する。従って、水素イオン濃度が11よりも小さい溶液を用意し、基板電位を負にすると、タンパク質分子は基板に吸着するはずである。実験では未飽和の水素イオン濃度5のリゾチーム溶液を使用した。電位を0の状態にして、まず基板のμmサイズの明瞭な表面像を得た。この状態から基板電位を低下させたところ、ある電位を境に像が不明瞭となった。この状態から電位を上げると再び基板表面像が得られたが、以前ほどは明瞭ではなくなっていた。また、基板表面像が得られた電位は像が不明瞭になった電位よりも高かった。このことはある基板電位よりも下でリゾチーム分子が基板に吸着したことを示しており、吸着電位と溶液水素イオン濃度から等電点を求めることが可能であることが明らかになった。臨界電位と水素イオン濃度の関係を求めるのが次の課題であるが、そのためには再現性良く臨界電位を求める手順を決めることが必要である。また、水の電気分解のため使用できる電位幅に制限が存在する。水素イオン濃度を適当な幅で変えて観察を行うことが必要になってくる。
    日本学術振興会, 萌芽的研究, 東北大学, 11874044
  • In situ study of protein crystallization at the molecular level using atomic force microscopy
    Grants-in-Aid for Scientific Research
    1998 - 1999
    DARBIN Stephen d.; SAZAKI Gen; MIYASHITA Satoru
    The goal of this work has been to extend the investigation of protein crystallization mechanisms to the level of individual molecules. Within this area, the research followed several directions : 1) use of atomic force microscopy (AFM) to follow the kinetics of protein crystal growth in situ, relating the observable parameters such as step velocity to molecular scale quantities such as bond energies ; 2) development of a modification of the conventional AFM technique to directly monitor single-molecule events during crystal growth, such as surface diffusion and incorporation ; 3) use of optical techniques to monitor properties which might be related to molecular level phenomena, such as alignment effects due to extremely high magnetic field, or changes in molecular hydration under high pressure. In addition, other research on crystal growth was carried out using the AFM and therefore considered to be indirectly supported. Regarding 1), AFM observation was used to elucidate the mechanism of impurity action in inhibiting crystal growth of tetragonal form lysozyme, which can be understood in terms of a step-blocking model. AFM was also used to investigate the kinetics of step motion on monoclinic lysozyme crystals, which could be related to the intermolecular "macrobonds" which determined the morphology of the crystal. In connection with 2), we developed a modified commercial atomic force microscope combined with a high-speed data acquisition system to pursue more direct single-molecule measurements. The AFM, operated in tapping mode without scanning, gave a signal representing sample height changes due to motion of the topmost protein molecule under the tip. A much improved signal-to-noise ratio can be obtained by using very small cantilevers ; with these, the system should be capable of the ultimate goal of single-molecule observation. As for area 3), fluorescence microscopy observations were used to demonstrate the role of molecular charge and crystal growth rate on impurity incorporation, and polarization rotation and in situ optical microscopy were used to study magnetic field effects, which could be understood via the observed reduction of solution convection, but had at most small influence on molecular-scale parameters such as alignment. Meanwhile, understanding of the action of ever-present impurities and means of optimizing crystal morphology through solution conditions and external fields have already enabled the production of higher quality crystals for structure determination at higher resolution
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), TOHOKU UNIVERSITY, 10304023
  • Growth of single crystalline films of bismuth based oxide superconductors by the liquid phase epitaxy method
    Grants-in-Aid for Scientific Research
    1997 - 1998
    MIYASHITA Satoru; SAZAKI Gen
    Growth conditions of Bi2212 superconducting films on the substrate crystal by the liquid phase epitaxial growth method using KCl as a solvent were investigated, In the case of the starting composition of Bi : Sr : Ca : Cu=2 : 2 : 1 : 2, the best growth temperature ranged from 840 to 870ﾟC.Under this condition, only the 2212 phase film grew on the substrate. In the early stage, the growth mechanism was the island growth and the changed to the continuous film growth mode. When islands met on the substrate, large steps occurred and this made film flattness poor. When we used the LaAlO3(1 10) substrate, however, grown 2201 films showed atomically flat area extending few micrometers square. When we used the NdGaO_3 * (001) substrate, nearly twin free film was obtained.
    Dessolution and solidification process of the oxide system of Bi-Sr-Ca-Cu-O was in situ observed with high temperature optical microscopy. We could determined the primary crystallization field (rough region of temperature and composition where the crystals grow as the first solid) for the self flux growth of the Bi based oxide superconductors system. This region we determined contained much bismuth than those ever reported. Traveling solvent floating zone method was applied on the basis of the knowledge of the primary crystallization field. To obtain single crystals thick in the crystallographic c-axis direction, the control of the nucleation by such as seeding was found to be needed. Using the seed crystal, we succeeded in continuous growth from the seed crystal and this indicated that the primary crystallization field we determined was reliable and useful. Next subject on the primary crystallization field is to clearly separate the 2212 phase and the 2201 phase region. We tried the liquid phase epitaxial method using the self flux, to fail. Corrosion of the substrates by the flux enabled us to obtaine the single film crystal. Further study is needed.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Tohoku University, 09650004
  • 光干渉法を用いたタンパク質結晶化過程のその場観察
    基礎科学研究助成
    Dec. 1996 - Nov. 1997
    佐﨑 元
    住友財団, Principal investigator, Competitive research funding
  • 光干渉法による低接触角の新測定法
    科学研究費助成事業
    1997 - 1997
    小松 啓; 中田 俊隆; 宮下 哲; 佐崎 元
    本研究は光干渉法を用いて、濡れ性の良好な固体と液体の接触角の計測法を確立するとともに、液体の接触角測定で重要なパラメータである雰囲気と温度を制御し、この新手法のもつ可能性を開発することを目標とした。現有の光学顕微鏡に長焦点低倍率のMichelson型二光束干渉対物レンズを装着し、干渉縞を使って濡れ性の良い固体と液体の接触角の計測を行えるようにした。測定の結果、不透明な液滴の場合、3°以下、透明な液滴の場合、液体の屈折率がわかっている場合は5°以下の接触角が正確に計測できることが明らかになった。この方法の利点は、従来の液滴側面から計測する方法に比べて、1.濡れの良い場合の低接触角の高精度の測定 2.液滴の形状の対称性が必要とならない点がある。一方、短所としては、接触角がこの値よりも大きいときは、液滴上での干渉縞が密になることと、液滴表面からの反射光が顕微鏡の光路に戻ってこないため、像が暗くなり、測定困難となる。この点の改良が今後の課題である。
    この装置に室温近くではペルチエ素子を使った温度セル、高温では光集光型の温度セルを使って接触角の測定を行った。特に対物レンズの焦点距離を長く(25mm)しているため、高温セルを使った測定が可能になっている。また、対象を酸化物を中心に考えているため、高温セルは雰囲気の酸素分圧を酸素メータと自動弁と調節器により自動制御できるようにした。これを使って白金基板上の酸化銅の接触角を計測した。1230℃で測定した場合、酸素分圧に対して45%付近で極小点をもつように変化した。また室温でグリセリン水溶液とマイカとの接触角を計測した。グリセリン濃度に対する接触角の変化を精密に測定できた。
    日本学術振興会, 萌芽的研究, 東北大学, 09875160
  • Nucleation and Growth Kinetics of Protein Crystals
    Grants-in-Aid for Scientific Research
    1997 - 1997
    KOMATSU Hiroshi; VEKILOV Peter; ROSENBERGER Franz; SAZAKI Gen; NAKADA Toshitaka; MIYASHITA Satoru
    Results obtained by this project were summarized as below.
    (1) Japanese team developed a Michelson Interferometer objective lens of super-long working distance (25.5 mm) with Nikon Co. Using this interferometer, a novel technique for determining solubility was developed, and solubilities of tetragonal and orthorhombic lysozyme crystal were detemined as a function of temperature for the first time.
    (2) Japanese team studied magnetic field effects on the crystallization of lysozyme, and found that a magnetic field (i) increased a growth rate and (ii) decreased a solubility. Equipment to measure magnetic birefringence was developed.
    (3) Japanese team highly-purified commercial lysozyme (99.9%) by purification technique developed by U.S.A.team. Growthprocess of lysozyme crystals were in situ observed by atomic force microscopy. It was found that small amount of impurity (1%) drastically decreased growth rate of (101) face of tetragonal crystal.
    (4) Japanese team developed a novel technique to measure impurity content and its distribution in the crystal with a fluorescense indicator. A novel mechanism of the impurity incorporation into the crystal was proposed.
    (5) U.S.A.team analyzed the concentration distribution around growing lysozyme crystals using computer simulation technique. Japanese team measured the actual concentration distribution around the crystal by interferometry. These two results were compared each other and found that they mostly agreed. It was found that buoyancy driven convection can be stopped when the thickness of the solution is smaller than l50オm.
    (6) Japanese team observed the concentration distribution around lysozyme crystals under lg to micro-g using free fall facilities. The changes in the concentration distribution were analyzed.
    Japan Society for the Promotion of Science, Grant-in-Aid for international Scientific Research, Tohoku University, 09044055
  • タンパク質（コンカナバリンA）の結晶成長過程の動的研究
    平成７年度科学研究費補助金，奨励研究(A)
    Apr. 1995 - Mar. 1996
    佐﨑 元
    Principal investigator, Competitive research funding
  • Nucleation and Growth Kinetics in Protein Crystallization
    Grants-in-Aid for Scientific Research
    1995 - 1996
    KOMATSU Hiroshi; THOMAS Bill; VEKILOV Peter; ROSENBERGER Franz; SAZAKI Gen; NAKADA Toshitaka; MIYASHITA Satoru; OBINATA Masuo; MUSHOL Martin
    Achievements of this year are as follows ;
    1. The Japanese group (J-group) measured solubilities of tetragonal, orthorhombic and triclinic form of hen egg white lysozyme (HEW lysozyme) using two beam interferometry.
    2. J-group developed an interferometic method to measure the refractive index inside crystals (HEW lysozyme).
    3. J-group got highly purified HEW lysozyme samples using HPLC.With this sample, they observed crystal interfaces using atomic force microscopy. This result was discussed with the American group (A-group) comparing with A-group's result.
    4. J-group tried to perform crystallization of HEW lysozyme in a high magnetic field. And they found that it could control the nucleation rate and orientation of crystals.
    5. Appoferritin (A-group) and ferritin (J-group) were highly purified and then crystallized. They showed again that removement of impurities is indispensable for growth of crystals of high quality. J-group made a morphodrom of ferritin.
    6. A-group performed light scattering experiments of HEW lysozyme solution and discuss the aggregation process. They estimated the second virial coefficient of the solution and discussed relation between ion intensity and intermolecular interaction.
    7. A-group precisely measured topography of vicinal surface with use of the laser interferometry and obtained time evolution of normal and step growth rates and slope of the vicinal surfaces.
    8. A-group found that there existed a region where HEW lysozyme solution separated into two liquid phases. They made a phase diagram for this segregation with use of the light scattering technique.
    9. In order to estimate the solution layr thickness where convection is ignored, A-grup performed computer simulation of the concentration profiles around a growing crystal changing thickness of the solution layr. J-group measured concentration profiles around a growing lysozyme crystal changing the thickness of the cell. These results were compared each other.
    10. J-group measured solubility of HEW lysozyme in situ in high pressure. Pressure dependence of the growth rate was also studied.
    Japan Society for the Promotion of Science, Grant-in-Aid for international Scientific Research, TOHOKU UNIVERSITY, 07044057
  • Crystal Growth of Protein
    1994
    Competitive research funding
■ Industrial Property Rights
  • 光学顕微鏡と光学的観察方法
    Patent right
    特開2005-309415
  • 有機半導体薄膜のエピタキシャル成長
    Patent right
    特開2005-79535A
  • 水素生成光デバイス
    Patent right
    特開2003-238104

Research Profiles

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