Multicolor stimulated Raman and fluorescence imaging for investigating lipid metabolism

Simultaneous localization of multiple cellular components related to the cellular activities, e.g. metabolism of small molecules, is not well understood due to the intrinsic limitations of fluorescence imaging technologies. The broad fluorescence emission often limits the available color number to ~4. Additionally, staining of small metabolic precursors is still difficult using fluorophores because the relatively large size of fluorophores will affect the regular metabolism of small molecules. Here, we apply our newly developed high-speed multicolor stimulated Raman and fluorescence imaging platform to observe and investigate lipid metabolism in live HeLa cells. Metabolic products generated from the deuterated palmitic acid were imaged in the Raman silent region using stimulated Raman scattering microscopy; meanwhile four kinds of organelles were imaged using fast-tunable confocal fluorescence microscopy. By taking advantages of both stimulated Raman imaging and fluorescence imaging, it enables the localization of multiple components up to five during cellular metabolism in live cells, which can be a helpful method to research complex biomedical processes.