Super-resolution Raman probe imaging

Super-resolution vibrational microscopy holds great promise for enhancing the multiplexing capabilities of nanometer-scale biological imaging due to the narrower spectral linewidth of molecular vibrations compared to fluorescence. However, current super-resolution vibrational microscopy techniques are plagued by several limitations, such as the requirement for cell fixation, high power consumption, or complex detection setups. Here we describe our recent demonstration of reversible saturable optical Raman transitions (RESORT) microscopy, which addresses these limitations by utilizing photoswitchable stimulated Raman scattering (SRS). To realize RESORT, we developed a bright photoswitchable Raman probe (DAE620). Leveraging the signal depletion capability of DAE620 through a donut-shaped beam, we successfully demonstrate super-resolution vibrational imaging of mammalian cells. This approach provides excellent chemical specificity and achieves spatial resolution beyond the optical diffraction limit. The present results indicate the potential of RESORT microscopy for multiplexed super-resolution imaging of live cells.