2006 Fiscal Year Final Research Report Summary
Time-resolved spectroscopy of a specific, single fluorescent protein molecule in a living cell
| Project/Area Number |
17360031
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 |
ITOH Kazuyoshi Osaka University, Graduate School of Engineering, Professor (80113520)
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| Co-Investigator(Kenkyū-buntansha) |
KONISHI Tsuyoshi Osaka University, Graduate School of Engineering, Assoc. Prof. (90283720)
MATSUNAGA Sachihiro Osaka University, Graduate School of Engineering, Lecturer (40323448)
OZEKI Yasuyuki Osaka University, Graduate School of Engineering, Assist. Prof. (60437374)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Living cells / femtosecond laser / fluorescent protein / nonlinear optics / stimulated parametric emission |
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| Research Abstract |
In the recent post-genome biological research field, there is a growing demand for exploring the function, mechanism, interaction, and network of proteins, which are the physical basis of life. In particular, it is of great interest to analyze the interactions among protein molecules by use of low-invasive visualization tools.
The objective of this research was to provide optical means for analyzing the interactions among protein molecules. The first target was to improve the fluorescence yield of fluorescent proteins through the investigation on the fluorescence mechanisms of fluorescent proteins with the femtosecond time-resolved micro-spectroscopy. Through the experiment, we succeeded in the two-photon fluorescence conversion of a fluorescent protein Kaede. This technique turned out to be a powerful tool for exploring the function of a single organelle in a living cell. Then we realized that, by irradiating dual-wavelength femtosecond pulses, a strong optical signal is generated through the four-wave mixing process due to electronic optical nonlinearity, which we called stimulated parametric emission, SPE. We constructed a SPE microscopy system, which was found to be a useful tool for the label-free observation of living cells. We also succeeded in (a) the sensitive detection of SPE signals by use of a spectral interferometric technique, (b) the application of the SPE microscopy to the three-dimensional profiling of refractive index distribution of non-biomedical samples, and (c) the development of a novel technique of dispersion compensation of a microscope objective lens for its application to ultrafast nonlinear optical microscopy using ultrashort optical pulses in few-cycle regime. To summarize, through these achievements, we have successfully developed and demonstrated novel approaches for exploring interactions of protein molecules by using femtosecond laser pulses.
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