Development of an Ultraviolet Raman Microspectrometer Applicable to Structural Analyzes of Cells

拉曼显微光谱学是一种非破坏性研究微米级颗粒结构的有用技术。另一方面，紫外共振拉曼光谱提供了有关蛋白质和核酸结构的关键信息。在这项研究中，我们开发了一种紫外拉曼显微光谱仪，以开发这两种光谱方法的实用价值。显微光谱仪由连续波紫外激光器、紫外显微镜和拉曼光谱仪组成。紫外光光束是由Ar~(2+)激光对可见光进行倍频得到的。紫外线显微镜是专门为紫外线区域的高通量和显微图像的高空间分辨率而设计的。用紫外光照射显微镜下的样品，采集同一物镜下的拉曼散射光，然后将其引导到我们实验室已经研制的拉曼光谱仪。我们利用新研制的紫外拉曼光谱仪成功地记录了一些拉曼光谱，但该光谱仪的灵敏度不足以研究活细胞中的微粒结构。我们计划使用超高灵敏度的CCD探测器来探测即使是极微弱的拉曼光，并将紫外拉曼显微光谱仪应用于活细胞的结构分析。

Raman microspectroscopy is a useful technique to investigate the structures of micrometer-sized particles in a non-destructive manner. On the other hand, ultraviolet resonance Raman spectroscopy provides key information on the structures of proteins and nucleic acids. In this study, we have developed an ultraviolet Raman microspectrometer to exploit the utilities of both spectroscopic methods. The microspectrometer consists of a continous-wave ultraviolet laser, an ultraviolet microscope, and a Raman spectrometer. The ultraviolet laser beam is obtained by frequency-doubling visible laser light from an Ar^+ laser. The ultraviolet microscope is specially designed for high throughput in the ultraviolet region and high spatial resolution of microscopic images. Samples under a microscope objective are irradiated with ultraviolet laser light and the Raman scattered light was collected with the same objective and then guided to the Raman spectrometer, which has already been developed in our laboratory. We have succeeded to record some Raman spectra by using newly developed ultraviolet Raman microspectrometer.However, the sensitivity of the microspectrometer is not enough to investigate the structures of microparticles in living cells. We are planning to use an ultra-high-sensitivity CCD detector to detect even extremely weak Raman light and to apply the ultraviolet Raman microspectrometer to structural analyzes of living cells.