LaSIE   People

Katsumasa FUJITA

Associate Professor, Ph. D.
Department of Applied Physics, Osaka University
2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
office: Appl. Phys. Build, Room P2-313 (map)
phone: +81-6-6879-7847

Research Topics

HeLa cell stained with AttoR6G phalloidin

Super-resolution fluorescence microscopy : SAX microscopy
We are developing optical microscopy techniques which can resolve fine structures of samples with the spatial resolution beyond the diffraction limit of light. By using saturated excitation (SAX) of fluorescence molecules, we induce nonlinear fluorescence emission that contribute to produce super-resolution images. The SAX miroscope can be realized by simply modulating laser intensity and demodulating fluorescence signal in a typical confocal microscope.

The figure shows the fluorescence images of a HeLa cell stained with AttoR6G phalloidin (xz cross-section). SAX microscopy can image fine structures that can not be resolved by conventional confocal microscopy.

Chu et al., Phys. Rev. Lett., (2014).
Yamanaka et al., J. Biomed. Opt. (2013).
Yamanaka et al., Biomed Opt. Express (2011).
Kawano et al., Appl. Phys. Express (2011).
Fujita et al., Phys. Rev. Lett. (2007)
Yamanaka et al., J. Biomed. Opt. (2008).

753 cm-1 : Cytochrome
1686 cm-1 : Protein
2852 cm-1 : Lipid

Movie by Raman
Cell division: cytokinesis
Cell division: mitosis
Raman microscopy for imaging of biological samples
We are developing Raman microscopes to image and analyze biomolecules in living cells. Raman scattering spectra show molecular vibrations in a sample, that contain rich information about species, conditions and environments of molecules. We have developed a slit-scanning Raman microscope and applied it to imaging of biomolecule dynamics in a living cell. We are also developing a higher-sensitive Raman detection technique for cellular imaging by using surface-enhanced Raman scattering and Raman tags to image small molecules.

The figure shows a Raman image of living HeLa cells. Molecular vibrations detected by Raman spectra produce the distribution of proteins and lipids in the cells.

Wanatabe et al., Nat. Commun. (2015).
Palonpon et al, Nat. Protoc. (2013).
Palonpon et al, Curr. Opin. Chem. Biol. (2013).
Yamakoshi et al, JACS (2012).
Okada et al., PNAS (2012).
Ando et al., Nano Lett. (2011).
Yamakoshi et al., JACS (2011).
Fujita et al., J. Biomed. Opt. (2009).
Fujita et al., Mol. Cells (2008).
Hamada et al., J. Biomed. Opt. (2008).

Original Papers
  • J. Ando, M. Asanuma, K. Dodo, H. Yamakoshi, S. Kawata, K. Fujita, M. Sodeoka, "Alkyne-tag SERS screening and identification of small-molecule-binding sites in protein," J. Am. Chem. Soc. (accepted).
  • Y.-T. Chen, P.-H. Lee, P.-T. Shen, J. Launer, R. Oketani, K.-Y. Li, Y.-T. Huang, K. Masui, S. Shoji, K. Fujita, S.-W. Chu, “Study of nonlinear plasmonic scattering in metallic nanoparticles,” ACS Photonics (online)
  • H.-Y. Wu, Y.-T. Huang, P.-T. Shen, H. Lee, R. Oketani, Y. Yonemaru, M. Yamanaka, S. Shoji, S. Kawata, C.-W. Chang, K.-H. Lin, K. Fujita, S.-W. Chu, "Ultrasmall all-optical plasmonic switch and its application to superresolution imaging," Sci. Rep., 6: 24293 (2016).
  • H. Lee, K.-Y. Li, Y.-T. Huang, P.-T. Shen, G. Deka, R. Oketani, Y. Yonemaru, M. Yamanaka, K. Fujita, S.-W. Chu, "Measurement of scattering nonlinearities from a single plasmonic nanoparticle,"J. Vis. Exp. (107), e53338 (2016).
  • Y. Kumamoto, K. Fujita, N. I. Smith, S. Kawata, "Deep-UV biological imaging by lanthanide ion molecular protection," Biomed. Opt. Express, 7 (1), 158-170 (2016).
  • K. Watanabe, A. F. Palonpon, N. I. Smith, L.-d. Chiu, A. Kasai, H. Hashimoto, S. Kawata, K. Fujita, "Structured line illumination Raman microscopy," Nat. Commun. 6:10095 (2015).
  • K. Bando, N. I. Smith, K. Fujita, S. Kawata, "Analysis of dynamic SERS spectra measured with a nanoparticle during intracellular transportation in 3D," J. Opt., 17, 114023 (2015).
  • M. Yamanaka, K. Saito, N. I. Smith, Y. Arai, K. Uegaki, Y. Yonemaru, K. Mochizuki, S. Kawata, T. Nagai, K. Fujita, "Visible-wavelength two-photon excitation microscopy for fluorescent protein imaging," J. Biomed. Opt., 20 (10), 101202 (2015).
  • A. Hashimoto, Y. Yamaguchi, L.-d. Chiu, C. Morimoto, K. Fujita, M. Takedachi, S. Kawata, S. Murakami, E. Tamiya, "Time-lapse Raman imaging of osteoblast differentiation," Sci. Rep., 5, 12529 (2015).
  • Y. Yonemaru, A. F. Palonpon, S. Kawano, N. I. Smith, S. Kawata, and K. Fujita, "Super-spatial- and -spectral-resolution in vibrational imaging via saturated coherent anti-Stokes Raman scattering," Phys. Rev. Applied, 4, 014010 (2015).
  • Z. Zheng, S. Mizukami, K. Fujita, and K. Kikuchi, "An enzyme-responsive metal-enhanced near-infrared fluorescence sensor based on functionalized gold nanoparticles," Chem. Sci., 6, 4934-4939 (2015).
  • T. Ichimura, L.-d. Chiu, K. Fujita, H. Machiyama, S. Kawata, T. M. Watanabe, H. Fujita, "Visualizing the appearance and disappearance of the attractor of differentiation using Raman spectral imaging," Sci. Rep., 5, 11358 (2015).
  • D. K. Tiwari, Y. Arai, M. Yamanaka, T. Matsuda, M. Agetsuma, M. Nakano, K. Fujita, T. Nagai, "Fast positively photoswitchable fluorescent protein for ultra-low laser power RESOLFT nanoscopy," Nat. Methods, 12, 515-518 (2015).
  • J. Ando, M. Kinoshita, J. Cui, H. Yamakoshi, K. Dodo, K. Fujita, M. Murata, M. Sodeoka, "Sphingomyelin distribution in lipid rafts of artificial monolayer membranes visualized by Raman microscopy," Proc. Natl. Acad. Sci., 112 (15), 4558-4563 (2015).
  • K. Mochizuki, L. Shi, S. Mizukami, M. Yamanaka, M. Tanabe, W.-T. Gong, A. F. Palonpon, S. Kawano, S. Kawata, K. Kikuchi, K. Fujita, "Nonlinear fluorescence imaging by photoinduced charge separation," Jpn. J. Appl. Phys., 54, 042403 (2015).
  • A. J. Hobro, N. Pavillon, K. Fujita, M. Ozkan, C. Coban, N. I. Smith, "Label-free Raman imaging of the macrophage response to the malaria pigment hemozoin," Analyst, 140, 2350-2359 (2015).
  • Y. Saito and K. Fujita, "Direct electron density modulation of surface plasmons with a scanning electron microscope," Appl. Phys. Express 8, 015001 (2015).
  • H. Yamakoshi, A. Palonpona, K. Dodoa, J. Ando, S. Kawata, K. Fujita, M. Sodeoka, "A sensitive and specific Raman probe based on bisarylbutadiyne for live cell imaging of mitochondria," Bioorg. Med. Chem. Lett. 25 (3), 664-667 (2015).
  • L.-d. Chiu, A. F. Palonpon, N. I. Smith, S. Kawata, M. Sodeoka, K. Fujita, "Dual-polarization Raman spectral imaging to extract overlapping moleclular fingerprints of living cells," J. Biophotonics, 8 (7), 546-6554 (2015).
  • H. Lee, R. Oketani, Y.-T. Huang, K.-Y. Li, Y. Yonemaru, M. Yamanaka, S. Kawata, K. Fujita, S.-W. Chu, "Point spread function analysis with saturable and reverse saturable scattering," Opt. Express, 22 (21), 26016 (2014).
  • N. I. Smith, K. Mochizuki, H. Niioka, S. Ichikawa, N. Pavillon, A. J. Hobro, J. Ando, K. Fujita, Y. Kumagai, "Laser-targeted photofabrication of ​gold nanoparticles inside cells," Nat. Commun., 5, 5144 (2014).
  • K.-C. Huang, K. Bando, J. Ando, N. I. Smith, K. Fujita, S. Kawata, "3D SERS (surface enhanced Raman scattering) imaging of intracellular pathways," Methods, 68 (2), 348 (2014).
  • Y. Yonemaru, M. Yamanaka, N. I. Smith, S. Kawata, K. Fujita, "Saturated excitation microscopy with optimized excitation modulation," ChemPhysChem, 15 (4), 743 (2014).
  • A. Hashimoto, L.-d. Chiu, K. Sawada, T. Ikeuchi, K. Fujita, M. Takedachi, Y. Yamaguchi, S. Kawata, S. Murakami, E. Tamiya, "In situ Raman imaging of osteoblastic mineralization," J. Raman Spectrosc., 45 (2), 157 (2014).
  • S.-W. Chu, T.-Y. Su, R. Oketani, Y.-T. Huang, H.-Y. Wu, Y. Yonemaru, M. Yamanaka, H. Lee, G.-Y. Zhuo, M.-Y. Lee, S. Kawata, and K. Fujita, "Measurement of a saturated emission of optical radiation from gold nanoparticles: application to an ultrahigh resolution microscope," Phys. Rev. Lett., 112 (1), 017402 (2014). (highlighted in APS physics spotlights)
  • T. Ichimura, L.-d. Chiu, K. Fujita, S. Kawata, T. M. Watanabe, T. Yanagida, H. Fujita, "Visualizing cell state transition using Raman spectroscopy," PLOS ONE, 9 (1), e84478 (2014).
  • S.-W. Chu, H.-Y. Wu, Y.-T. Huang, T.-Y. Su, H. Lee, Y. Yonemaru, M. Yamanaka, R. Oketani, S. Kawata. S. Shoji, and K. Fujita, "Saturation and reverse saturation of scattering in a single plasmonic nanoparticle," ACS Photonics, 1 (1), 32-37 (2014). (introduced in Nature Photonics, 8, 92 (2014).
  • H. Yamakoshi, A. F. Palonpon, K. Dodo, J. Ando, S. Kawata, K. Fujita, M. Sodeoka, "Simultaneous imaging of protonated and deprotonated carbonylcyanide p-trifluoromethoxyphenylhydrazone in live cells by Raman microscopy," Chem Commun., 50, 1341 (2014).
  • M. Yamanaka, Y. Yonemaru, S. Kawano, K. Uegaki, N. I. Smith, S. Kawata, K. Fujita, "Saturated excitation microscopy for sub-diffraction-limited imaging of cell clusters," J. Biomed. Opt., 18 (12), 126002 (2013).
  • M. Yamanaka, K. Saito. N. I. Smith, S. Kawata, T. Nagai, K. Fujita, "Saturated excitation (SAX) of fluorescent proteins for sub-diffraction-limited imaging of living cells in three dimensions," Interface FOCUS, 3, 20130007 (2013).
  • A. F. Palonpon, J. Ando, H. Yamakoshi, K. Dodo, M. Sodeoka, S. Kawata, K. Fujita, "Raman and SERS microscopy for molecular imaging of live cells," Nat. Protoc., 8, 677 (2013).
  • T. Shimozawa, K. Yamagata, T. Kondo, S. Hayashi, A. Shitamukai, D. Konno, F. Matsuzaki, J. Takayama, S. Onami, H. Nakayama, Y. Kosugi, T. M. Watanabeg, K. Fujita, Y. Mimori-Kiyosue, "Improving spinning disc confocal microscopy by preventing pinhole cross-talk for intravital imaging," Proc. Nat. Acad. Sci. USA., 110 (9), 3399 (2013).
  • N. Pavillon, K. Bando, K. Fujita, and N. I. Smith, "Feature-based recognition of Surface-enhanced Raman spectra for biological targets," J. Biophoton., 6 (8), 587 (2013).
  • M. Okada, N. I. Smith, A. F. Palonpon, H. Endo, S. Kawata, M. Sodeoka, K. Fujita, "Label-free Raman observation of cytochrome c dynamics during apoptosis," Proc. Natl. Acad. Sci. USA, 109 (1) 28-32 (2012).
  • H. Yamakoshi ,K. Dodo , A. F. Palonpon , J. Ando , K. Fujita , S. Kawata, and M. Sodeoka, "Alkyne-tag Raman imaging for visualization of mobile small molecules in live cells," J. Am. Chem. Soc., 134, 20681-20689 (2012).
  • Y. Masago, A. Hosoya, K. Kawasaki, S. Kawano, A. Nasu, J. Toguchida, K. Fujita, H. Nakamura, G. Kondoh, and K. Nagata, "Molecular chaperone Hsp47 is essential for cartilage and endochondral bone formation," J. Cell Science, 125 (Pt 5), 1118-1128 (2012).
  • J. Ando, K. Fujita, N. I. Smith and S. Kawata, "Dynamic SERS imaging of cellular transport pathways with endocytosed gold nanoparticles," Nano Lett., 11 (12), 5344-5348 (2011).
  • M. Yamanaka, Y-. K. Tzeng, S. Kawano, N. I. Smith, S. Kawata, H-. C. Chang, and K. Fujita, "SAX microscopy with fluorescent nanodiamond probes for high-resolution fluorescence imaging," Biomed. Opt. Express, 2 (7), 1946-1954 (2011)
  • M. Honda, Y. Saito, N. I. Smith, K. Fujita, and S. Kawata, "Nanoscale heating of laser irradiated single gold nanoparticles in liquid," Opt. Express, 19 (13), 12375-12383 (2011).
  • M.-L. Zheng, K. Fujita, W.-Q. Chen, X.-M. Duan, and S. Kawata, "Two-photon excited fluorescence and second-harmonic generation of the DAST organic nanocrystals," J. Phys. Chem. C, 115 (18), 8988-8993 (2011).
  • H. Yamakoshi, K. Dodo, M. Okada, J. Ando, A. Palonpon, K. Fujita, S. Kawata, and M. Sodeoka, "Imaging of EdU, an alkyne-tagged cell proliferation probe, by Raman microscopy," J. Am. Chem. Soc., 133 (16), 6102–6105 (2011).
  • S. Kawano, N. I. Smith, M. Yamanaka, S. Kawata and K. Fujita, "Determination of the expanded optical transfer function in saturated excitation imaging and high harmonic demodulation," Appl. Phys. Express, 4, 042401 (2011).
  • M.-L. Zheng, K. Fujita, W.-Q. Chen, N. I. Smith, X.-M. Duan, and S. Kawata, "Comparison of staining selectivity of subcellular structures by carbazole-based cyanine probes for nonlinear optical microscopy," ChemBioChem., 12, 52-55 (2011).
  • R. J. Milewski, Y. Kumagai, K. Fujita, D. M. Standley, N. I. Smith, "Automated processing of label-free Raman microscope images of macrophage cells with standardized regression for high-throughput analysis," Immunome Research, 6, 11 (2010).
  • M.-L. Zheng, W.-Q. Chen, K. Fujita, X.-M. Duan, and S. Kawata, "Dendrimer adjusted nanocrystals of DAST: organic crystal with enhanced nonlinear optical properties," Nanoscale, 2, 913 - 916 (2010).
  • T. Minamikawa, M. Hashimoto, K. Fujita, S. Kawata, and T. Araki, "Multi-focus excitation coherent anti-Stokes Raman scattering (CARS) microscopy and its applications for real-time imaging," Opt. Express, 17, 9526-9536 (2009). (selected for the publication in Virtual Journal for Biomedical Optics, 4 (8), 2009)
  • K. Fujita, S. Ishitobi, K. Hamada, N. I. Smith, A. Taguchi, Y. Inouye, and S. Kawata, "Time-resolved observation of surface-enhanced Raman scattering from gold nanoparticles during transport through a living cell," J. Biomed. Opt. 14, 024038 (2009).
  • M. Ogawa, Y. Harada, Y. Yamaoka, K. Fujita, H. Yaku, T. Takamatsu, "Label-free biochemical imaging of heart tissue with high-speed spontaneous Raman microscopy," Biochem. Biophys. Res. Communn., 382, 370-374 (2009).
  • J. Ando, N. I. Smith, K. Fujita, and S. Kawata, "Photogeneration of membrane potential hyperpolarization and depolarization in non-excitable cells," Eur. Biophys. J., 38, 255-262 (2009).
  • H. Ishitobi, T. Kai, K. Fujita, Z. Sekkat, and S. Kawata, "On fluorescence blinking of single molecules in polymers," Chem. Phys. Lett. 468, 234-238 (2009).

Review Articles

Invited Talks (International only)

  • M. Hashimoto, T. Ichimura, K. Fujita, "CARS Microscopy: Implementation of Nonlinear Vibrational Spectroscopy for Far-Field and Near-Field Imaging," in Raman Imaging, Springer Series in Optical Sciences 168 (A. Zoubir Ed., Springer-Verlag Berlin Heidelberg 2012).
  • Yasuaki Kumamoto, Nicholas Isaac Smith, Katsumasa Fujita, Jun Ando and Satoshi Kawata, "Optical Techniques for Future Pacemaker Technology," in Modern Pacemakers - Present and Future (M. K. Da ed. InTech 2011).
  • N. I. Smith, S. Kawano, M. Yamanaka, and K. Fujita, "Nonlinear Fluorescence Imaging by Saturated Excitation," in Nanoscopy and Multidimensional Optical Fluorescence Microscopy, pp. 2-1 ~ 2-16 (A. Diaspro Ed., Chapman and Hall/CRC press, April 2010).
  • P. Verma, K. Fujita, T. Ichimura, and S. Kawata, "Raman, CARS and near-field Raman-CARS microscopy for cellular and molecular imaging," in "Nano Biophotonics - Science and Technology -," pp. 57-71 (H. Masuhara, S. Kawata, and F. Tokunaga Ed. Elservier B.V., Amsterdam, 2007).
  • K. Fujita, N. Smith, and O. Nakamura, "Nonlinear optical imaging and stimulation of living cells," in Nanophotonics -Intengrating photochemistry, Optics and Nano/Bio Materials Studies - (H. Masuhara and S. Kawata Ed. Elsevier B.V., Amsterdam, 2004).
  • K. Fujita and T. Takamatsu, "Real-time in situ calcium imaging with single and two-photon confocal microscopy," in Confocal and two-photon microscopy: Foundation, Application and Advances (A. Diaspro Ed. John Wiley & Sons, Inc., New York, 2001).

    ..... and more


  • "Raman Imaging of Live Cells," Spectroscopy, 18 Nov (2014).
  • "Harmonic Microscopy," RIKEN Research 14 Mar (2008).
  • Richard Gaughan, "Laser Technique Monitors Calcium," PHOTONICS SPECTRA, January, p.65 (2002).
  • Richard Gaughan, "Near-infrared laser generates calcium waves," Biophotonics International, March, p.54 (2002).