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

描述(申请人提供)：小分子，如代谢物和药物，是生命有机体生物化学的关键，因为它们的多样性和存在的绝对数量。与蛋白质、DNA和mRNA等大分子对应物种不同，这些物种中的大多数在活细胞或有机体中都是看不见的，因为技术上的困难。给它们贴上笨重的荧光标签会扰乱它们的功能。基于拉曼散射的无标记光学成像是非常理想的，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度，但其灵敏度低且采集时间长。我们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、快速图像获取、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，我们实验室已经在进行脂肪代谢和药物在组织中分布的研究。我们建议继续这一开创性的发展，以探索脂代谢，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类，如饱和和不饱和脂类和胆固醇，而且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，而不使用微扰标记。这些新的实验无疑将允许进行新的观察，从而丰富我们对细胞生物化学的知识。我们还将开发全光学癌症标记物，并使用SRS为脑肿瘤的术中成像带来新的范例，通过缩短手术时间和更准确地定义肿瘤边缘来改善手术结果。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。 与公共卫生相关：在没有标记的活细胞和生物体中可视化代谢产物和药物等小分子的能力将彻底改变生物医学研究，特别是脂代谢、药代动力学和癌症诊断。我们建议将最近发展的受激拉曼散射显微技术扩展到基于分子的固有振动频率提供快速、灵敏和非侵入性的成像，以便选择性地绘制脂类、蛋白质、葡萄糖、胆固醇、ADP、ATP、叶酸和小分子药物等物种的分布。这项技术将使我们在生命系统中实时监测生物化学的能力发生前所未有的变化，并导致术中成像技术的潜在突破，以快速和准确地识别肿瘤。

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. PUBLIC HEALTH RELEVANCE: The ability to visualize small molecules such as metabolites and drugs in living cells and organisms without labels will revolutionize biomedical research, particularly lipid metabolism, pharmacokinetics and cancer diagnosis. We propose to extend the recently developed stimulated Raman scattering microscopy technique to offer rapid, sensitive and noninvasive imaging based on intrinsic vibrational frequencies of molecules, in order to selectively map the distributions of lipids, protein, glucose, cholesterol, ADP, ATP, folate and small molecule drugs, among other species. This technology will make an unprecedented transformation of our ability to monitor biochemistry in real time in living systems, and lead to a potential breakthrough in intra-operative imaging for rapid and precise tumor identification.