Stimulated Raman Imaging of Lipids Droplets

Lipids are abundant in C-H groups. Thus in their Raman spectrum, the relatively isolated peaks associated with C-H bond vibrational states at 2845 cm provide a unique signature for lipids inside a cell, distinguishing them from other chemical species. Stimulated Raman scattering (SRS) microscopy allows vibrational contrast mechanism for imaging with high spectral and spatial resolution along with three-dimensional sectioning. SRS has proven to be particularly powerful for studying lipid rich structures. Additionally, lipid droplets (LDs) provide an especially strong signal for SRS microscopy.In this paper, the implementation of a microscope based on the femtosecond stimulated Raman scattering (f- SRS) spectroscopy not commercially available, working into the C-H region or O-H region (2800 - 3200 cm) in stimulated Raman gain (SRG) modality is outlined. In addition, an investigation of LDs in fixed adipocytes is reported.