2004 Fiscal Year Final Research Report Summary
Nonlinear nano-optics of a single cell
| Project/Area Number |
14205013
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Osaka University |
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Principal Investigator |
FUJITA Katsumasa Osaka University, Graduate School of Engineering, Assistant Professor, 大学院・工学研究科, 助手 (80362664)
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| Co-Investigator(Kenkyū-buntansha) |
OYAMADA Masahito Kyoto Prefectural University of Medicine, Department of Pathology and Cell Regulation, Associate Professor, 大学院・医学研究科, 助教授 (30183255)
INOUE Yasushi Osaka University, Graduate School of Engineering, Associate Professor, 大学院・生命機能研究科, 助教授 (60294047)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Nonlinear optical effect / Laser scanning microscopy / Second-harmonic generation / Coherent anti-Stokes Raman scattering / HeLa cells / Cardiomyocyte / Vibrational spectroscopy / Ultrashort pulsed laser |
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| Research Abstract |
In this research project, we developed techniques to measure nonlinear interaction between light and biomolecules that organizes cells. When near-infrared ultrashort pulsed laser are irradiated on biological specimen, nonlinear optical scatterings such as second-harmonic generation(SHG) and coherent anti-Stokes Raman scattering(CARS) are generated. The wavelength and intensity of the scattered light bring information of molecular species and orientation of proteins. We developed an SHG microscope and a CARS microscope and observed living cells.
Using SHG microscope, we observed rat cardiomyocytes and obtained SHG image of the cells. SHG specific to myosin filament was detected. SHG images of the cardiomyocytes show distribution of myosin filament in the cell. No pre-treatment of the cell such as dye labeling is needed for SHG imaging. we also observed HeLa cells using SHG microscope. Strong second-harmonic light is generated from tubulin only during mitosis. We think this is because dense tubulin that is generated during mitosis has strong anisotropy and gives efficient SHG.
We developed time-gated imaging system. Since SHG have nearly identical pulse width as excitation laser light, synchronous detection of SHG light improves the S/N ratio of SHG images.
We observed HeLa cells with a CARS microscope. Tuning the frequency difference of two incident lasers to vibration of lipid molecules, we obtained distribution of the lipid molecules in the cell. We observed cardiomyocytes with SHG and CARS microscope and obtained distribution of myosin and lipid molecules.
From these results, it appears that nonlinear optical effect can be applied to direct detection of biomolecules and microscopic observation of biological samples without conventional dye labeling technique.
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