Stimulated Raman imaging with chemical probes for subcellular bioanalysis

Innovations in optical spectroscopy and microscopy have revolutionized our understanding in biol. systems at subcellular levels. In this talk, I will present recent advances of two chem. imaging strategies addressing two fundamental challenges in optical bio-imaging. First, we devised a live-cell Bioorthogonal Chem. Imaging platform suited for probing the metabolic dynamics of small bio-mols., which cannot be effectively labeled by bulky fluorophores. This scheme couples the stimulated Raman scattering (SRS) microscopy, a nonlinear vibrational imaging modality that offers rich chem. information, with small vibrational tags including stable isotopes and triple bonds. We applied this platform to a variety of dynamical biol. systems and revealed previously less-known heterogeneity in metabolic signatures governing the obversed cell phenotypes. Second, we developed a supermultiplex optical imaging technique enabled by preresonant SRS microscopy of a newly designed palette of vibrational dyes. This work allows for simultaneous imaging of a large no. of mol. species in live cells and tissues with high sensitivity and specificity, bridging imaging and omics paradigms. Both phys. and chem. principles underlying the optical microscopy will be presented, as well as our recent efforts in biomedical applications including cancer- and neuronal- metab