Illuminating small bio-molecules: Stimulated Raman scattering imaging of vibrational tags

Abstract

Innovations in spectroscopy principles and microscopy technol. have significantly impacted modern biol. and medicine. While most of the contemporary bio-imaging modalities harness electronic transition, nuclear spin or radioactivity, vibrational spectroscopy has not been widely used yet. Here we will discuss an emerging chem. imaging platform, stimulated Raman scattering (SRS) microscopy, which can enhance the otherwise feeble spontaneous Raman eight orders of magnitude by virtue of stimulated emission. When coupled with stable isotopes (e.g., deuterium and 13C) or bioorthogonal chem. moieties (e.g., alkynes), SRS microscopy is well suited for probing in vivo metabolic dynamics of small bio-mols. which cannot be labeled by bulky fluorophores. Phys. principle of the underlying optical spectroscopy and exciting biomedical applications such as imaging lipid metab., protein synthesis, DNA replication, protein degrdn., RNA synthesis, glucose uptake, drug trafficking and tumor metab. will be presented.