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。我们用连续调Q的1064 nm谱线作为激励，用一种新型的InP/InGaAsP增强型CCD探测器进行探测。该系统的探测率至少比传统的傅立叶变换拉曼光谱仪高一个数量级，并且能够在不受荧光干扰的情况下记录高的S/N拉曼光谱。1)通过无荧光的近红外激发，我们现在能够测量人类肺组织的拉曼光谱。我们发现癌变肺组织的拉曼光谱与正常肺组织的拉曼光谱有很大的不同。这一结果表明，拉曼光谱可以非常清楚地区分癌组织和正常组织，在体内和非侵入性的癌症临床诊断方面具有巨大的潜力。为了便于活体拉曼测量，已经开发了一种光纤辐照/收集光学装置。2)利用632.8 nm激发的共聚焦拉曼光谱系统，首次观测到了酵母活细胞的时间和空间分辨拉曼光谱。观察到蛋白质、脂类和糖的时空相关拉曼谱带，反映了细胞核、线粒体和隔膜等细胞器分子组成随细胞周期的演变。3)将近红外拉曼系统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的荧光，但在1064 nm激发下没有观察到来自荧光的干扰。人们成功地探索了药物嵌入对DNA结构的影响。综上所述，本研究建立了近红外拉曼光谱的方法学，在生物医学应用中具有重要的应用价值。

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.