慶應義塾研究者情報データベース

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• マルチモーダル非線形光学顕微鏡

  

  マウス脳切片のCARSイメージ

  

  生命現象は、その機能発現に様々な生体分子が協働する複雑な物理化学現象です。生細胞内では、このようなダイナミックな現象が“ごく当たり前”に起こっており、その究極的な理解には、機能する分子をそのまま可視化することが必須です。ラマン分光法は、生細胞内にある分子分布や分子構造、動態を、非染色・非標識・非破壊・低侵襲でその場観察可能な、非常に強力な手法の一つです。私たちは、微弱なラマン散乱光を増幅する非線形ラマン散乱を用い、分子集合体から生細胞・生体組織まで、様々な系を「化学の眼」で可視化し、未知の生命現象の発見とその本質の解明に挑んでいます。

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• 博士（理学）, 東京大学, 課程, 2001年03月

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• Dynamic Raman Scattering: Molecular-Selective Correlation Spectroscopy for Diffusion Dynamics in Complex Systems

  Hiroi T., Samitsu S., Ishioka K., Kano H.

  Journal of Physical Chemistry C （Journal of Physical Chemistry C)  127 （ 21 ） 10245 - 10252 2023年06月

  ISSN  19327447

  　概要を見る

  Diffusion dynamics of polymers and colloidal dispersions at high concentrations have been widely studied using dynamic light scattering (DLS), a correlation spectroscopic method based on Rayleigh scattering. However, DLS has not been applied to complex systems such as biological cells because of its lack of molecular selectivity. Here, we propose dynamic Raman scattering (DRS), a novel molecular-selective correlation spectroscopic technique based on Raman scattering. We theoretically demonstrate that molecular-selective diffusion dynamics can be monitored by measuring the intensity fluctuation of coherent anti-Stokes Raman scattering in a phase-mismatching condition. We then experimentally prove the molecular selectivity of the DRS by extracting the polystyrene diffusion dynamics in a mixture of polystyrene and silica nanoparticles. We believe that DRS will be applicable for monitoring diffusion dynamics in complex dispersions without any pretreatment.

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• Label-Free Identification of Spore-Forming Bacteria Using Ultrabroadband Multiplex Coherent Anti-Stokes Raman Scattering Microspectroscopy

  Tanaka K., Oketani R., Terada T., Leproux P., Morono Y., Kano H.

  Journal of Physical Chemistry B （Journal of Physical Chemistry B)  127 （ 9 ） 1940 - 1946 2023年03月

  ISSN  15206106

  　概要を見る

  Spore-forming bacteria accumulate dipicolinic acid (DPA) to form spores to survive in extreme environments. Vibrational spectroscopy is widely used to detect DPA and elucidate the existence of the bacteria, while vegetative cells, another form of spore-forming bacteria, have not been studied extensively. Herein, we applied coherent anti-Stokes Raman scattering (CARS) microscopy to spectroscopically identify both spores and vegetative cells without staining or molecular tagging. The spores were identified by the strong CARS signals due to DPA. Furthermore, we observed bright spots in the vegetative cells in the CARS image at 1735 cm-1. The vegetative cells contained molecular species with C=O bonds because this vibrational mode was associated with the carbonyl group. One of the candidate molecular species is diketopimelic acid (DKP), a DPA precursor. This hypothesis was verified by comparing the spectrum obtained by the vegetative cells with that of the DKP analogue (ketopimelic acid) and with the result obtained by DFT calculation. The results indicate that the observed vegetative cell is in the sporulation process. CARS spectra can be used to monitor the maturation and preformation of spores.

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• Backward multiplex coherent anti-Stokes Raman (CARS) spectroscopic imaging with electron-multiplying CCD (EM-CCD) camera

  Murakami Y., Yoshimura M., Klement W.J.N., Oda A., Sakamoto R., Yakabe M., Matsumoto A., Oketani R., Leproux P., Ikenouchi J., Browne W.R., Kano H.

  OSA Continuum （OSA Continuum)  2 （ 9 ） 2044 - 2054 2023年

  　概要を見る

  A multiplex CARS imaging system, equipped with an EM-CCD camera, was developed to improve the sensitivity of backward CARS imaging in biological analysis using an inverted microscope. The signal-to-noise ratio was improved by a factor of ca. 3 compared to a conventional CCD mode through the use of EM gain. When imaging epithelial cells in the backward CARS configuration, intracellular organelles such as lipid droplets and nuclei were spectroscopically identified with an exposure time of only 100 ms/pixel.

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• Vapor-Induced Conversion of a Centrosymmetric Organic-Inorganic Hybrid Crystal into a Proton-Conducting Second-Harmonic-Generation-Active Material

  Yanagisawa J., Tanaka K., Kano H., Miyata K., Le Ouay B., Ohtani R., Ohba M.

  Inorganic Chemistry （Inorganic Chemistry)  61 （ 39 ） 15638 - 15644 2022年10月

  ISSN  00201669

  　概要を見る

  Chemical responsivity in materials is essential to build systems with switchable functionalities. However, polarity-switchable materials are still rare because inducing a symmetry breaking of the crystal structure by adsorbing chemical species is difficult. In this study, we demonstrate that a molecular organic-inorganic hybrid crystal of (NEt4)2[MnN(CN)4] (1) undergoes polarity switching induced by water vapor and transforms into a rare example of proton-conducting second-harmonic-generation-active material. Centrosymmetric 1 transforms into noncentrosymmetric polar 1·3H2O and 1·MeOH by accommodating water and methanol molecules, respectively. However, only water vapor causes a spontaneous single-crystal-to-single-crystal transition. Moreover, 1·3H2O shows proton conduction with 2.3 × 10-6S/cm at 298 K and a relative humidity of 80%.

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• Label-free visualization of cellular response to molecularly targeted agents using multiplex coherent anti-Stokes Raman scattering and third harmonic generation microscopy

  Oka Y., Shen L.T.W., Mori T., Iwamura T., Leproux P., Matsusaka S., Kano H.

  Applied Physics Express （Applied Physics Express)  15 （ 10 ）  2022年10月

  ISSN  18820778

  　概要を見る

  Cellular responses to molecularly targeted agents (gefitinib and osimertinib) have been observed in cultured cancer cells using ultra-broadband multiplex coherent anti-Stokes Raman scattering and third harmonic generation microscopy. Lipid droplets (LDs) appeared in the cells 48 h after the exposure of cancer cells to gefitinib. This was also observed in the gefitinib-resistant strain, and the accumulation of LDs was significant. When exposed to osimertinib, LDs were not as pronounced as those with gefitinib. These agents act on cells through different mechanisms.

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• Tribute to Hiro-o Hamaguchi: Expanding the Boundaries of Raman Spectroscopy

  Kano H., Bonn M., Zanni M., Tahara T.

  Journal of Physical Chemistry B (Journal of Physical Chemistry B)  128 ( 4 ) 883 - 885 2024年02月

  ISSN  15206106

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担当授業科目 【 表示 ／ 非表示 】

担当授業科目 【 表示 ／ 非表示 】

• 生命情報特別講義第１

  2024年度

• 生命情報輪講

  2024年度

• 生命系の物理化学第２

  2024年度

• 生命系の物理化学第１

  2024年度

• 現代生物学概論

  2024年度

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