Development and applications of highly-sensitive near-infrared multichannel Raman Spectroscopic system

建立了一套高灵敏度的近红外多通道拉曼光谱系统。我们使用连续调Q Nd：YAG激光器的1064 nm线作为激发和一个新的InP/InGaAsP增强CCD检测器。该系统的检测灵敏度比传统的FT-拉曼光谱仪高至少一个数量级，并且能够记录高信噪比的拉曼光谱而不受荧光的干扰。1)我们现在能够测量的拉曼光谱的人肺组织，凭借无荧光的近红外激发。我们发现肺癌组织的拉曼光谱与正常肺组织有很大的不同。这一结果表明，拉曼光谱非常清楚地区分癌组织和正常组织，并且它具有用于癌症的体内和非侵入性临床诊断的巨大潜力。为了便于体内拉曼测量，已经开发了光纤照射/收集光学器件。2)利用共焦拉曼显微光谱系统，在632.8 nm激发下，首次观测到了活酵母细胞的时间和空间分辨的拉曼光谱。观察到蛋白质、脂类和糖类的时间和空间依赖性拉曼谱带，反映了细胞器如细胞核、细胞器和隔膜中分子组成随细胞周期的演变。3)近红外拉曼系统已被应用于各种蛋白质和核酸样品的测量。尽管这些样品在可见光激发下发出强烈荧光，但在1064 nm激发下未观察到荧光干扰。成功地探索了药物嵌入DNA的结构变化。总之，本研究建立了近红外拉曼光谱的方法，这是特别有用的生物医学应用。

A highly sensitive near-infrared multichannel Raman spectroscopic system has been constructed. We use the 1064 nm line of a cw Q-switched Nd : YAG laser for excitation and a new InP/InGaAsP intensified CCD detector for detection. The system has a detectivity at least one order of magnitude higher than the conventional FT-Raman spectrometer and is capable of recording high S/N Raman spectra without the interference from fluorescence. 1) We are now able to measure the Raman spectra of human lung tissues, by virtue of fluorescence-free near-infrared excitation. We have found that the Raman spectra of cancered lung tissues are quite different from those of normal lung tissues. This result indicates that Raman spectroscopy distinguishes cancered and normal tissues very clearly and that it has a huge potential for in vivo and non-invasive clinical diagnosis of cancers. An optical-fiber irradiation/collection optics has been developed in order to facilitate in vivo Raman measurements. 2) Time- and space-resolved Raman spectra of a living yeast cell have been observed for the first time, using a confocal Raman microspectroscopic system with 632.8 nm excitation. Time- and space-dependent Raman bands of proteins, lipids, and sugars are observed, reflecting the evolution with the cell cycle of the molecular compositions in organelles like nucleus, mitochondrion and septum. 3) The near-infrared Raman system has been applied for the measurements of various protein and nucleic acid samples. Despite the fact that those samples fluoresce strongly with visible excitation, no interference from fluorescence has been observed with 1064 nm excitation. Structural change of DNA with drug intercalation has successfully been probed. In conclusion, the present research has established the methodology of near-infrared Raman spectroscopy, which is particularly useful in biomedical applications.