Imaging the Invisible with No Labels: A Major Opportunity in Biology and Medicine

描述（由申请人提供）：小分子如代谢物和药物对生物体的生物化学至关重要，因为它们具有很大的多样性和绝对的数量。与蛋白质、DNA和mRNA等大分子成分不同，由于技术上的困难，这些物种中的大多数在活细胞或生物体中是看不见的。用庞大的荧光标签标记它们会干扰它们的功能。基于拉曼散射的无标签光学成像是非常可取的，因为它通过分子振动光谱提供基于分子固有化学性质的对比，但受限于低灵敏度和较长的采集时间。我们的团队最近开发了受激拉曼散射（SRS）显微镜，它提供了前所未有的高灵敏度，快速图像采集，化学特异性和非侵入性的组合。SRS显微镜的发展引起了生物医学研究界的极大兴趣，我们的实验室已经在进行组织中的脂质代谢和药物分布的研究。我们建议继续开展开创性的研究，以探索脂质代谢，包括脂肪生成，脂肪分解和胰岛素抵抗。我们不仅将成像不同类型的脂质，如饱和和不饱和脂质和胆固醇，还将成像关键代谢物，如葡萄糖、ATP、ADP和小分子药物，所有这些都在活细胞和组织中，而不使用扰动标签。毫无疑问，这些新的实验将带来新的观察结果，从而丰富我们对细胞生物化学的认识。我们还将开发全光学肿瘤标志物，并利用SRS为脑肿瘤术中成像带来新的范例，通过缩短手术时间和更精确地定义肿瘤边缘来改善手术效果。SRS的广泛采用和新应用的发现将彻底改变生物医学研究的许多领域，包括脂质代谢、药代动力学和癌症诊断。

DESCRIPTION (provided by applicant): Small molecules such as metabolites and drugs are crucial to the biochemistry of living organisms because of their large diversity and the sheer number present. Unlike their large molecule counter parts such proteins, DNA and mRNA, most of these species are invisible in a living cell or organism because of technical difficulties. Tagging them with bulky fluorescent labels perturbs their function. Label-free optical imaging based on Raman scattering is highly desirable because it offers contrast based on the intrinsic chemical properties of molecules via molecular vibrational spectroscopy, but has been limited to low sensitivity and long acquisition times. Our group has recently developed stimulated Raman scattering (SRS) microscopy, which offers an unprecedented combination of high sensitivity, rapid image acquisition, chemical specificity and noninvasiveness. The development of SRS microscopy has generated a great of interest from the biomedical research community and studies of lipid metabolism and drug distributions in tissue are already underway in our laboratory. We propose to continue the pioneering development in order to probe lipid metabolism, including lipogenesis, lipolysis and insulin resistance. We will image not only different types of lipids, such as saturated and unsaturated lipids and cholesterol, but also key metabolites, such as glucose, ATP, ADP, and small molecule drugs as well, all in living cells and tissue without the use of perturbative labels. These new experiments will no doubt allow new observations that will enrich our knowledge of cellular biochemistry. We will also develop all-optical cancer markers and use SRS to bring about a new paradigm for intra-operative imaging of brain tumors, improving the surgical outcome by shortening surgery and allowing more precise definition of tumor margins. The widespread adoption of SRS and the discovery of new applications will revolutionize many areas of biomedical research, including lipid metabolism, pharmacokinetics and cancer diagnosis.