Coherent Raman scattering imaging of lipid metabolism in cancer

Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth. Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level. Although fluorescence microscopy has been commonly used for cancer research, bulky fluorescent probes can hardly label small lipid molecules without perturbing their biological activities. Such a challenge can be overcome by coherent Raman scattering (CRS) microscopy, which is capable of chemically selective, highly sensitive, submicron resolution and high-speed imaging of lipid molecules in single live cells without any labeling. Recently developed hyperspectral and multiplex CRS microscopy enables quantitative mapping of various lipid metabolites in situ. Further incorporation of CRS microscopy with Raman tags greatly increases molecular selectivity based on the distinct Raman peaks well separated from the endogenous cellular background. Owing to these unique advantages, CRS microscopy sheds new insights into the role of lipid metabolism in cancer development and progression. This review focuses on the latest applications of CRS microscopy in the study of lipid metabolism in cancer.