Molecular identification of second harmonic generation (SHG) sources in mouse brain by multimodal imaging with ultra-broadband multiplex coherent anti Stokes Raman scattering (CARS)

Abstract

Second harmonic generation imaging is a powerful tool for visualizing molecular structures in living organisms without the need for exogenous dyes. However, SHG signal lacks molecular specificity in identifying the source.This study aimed at molecular identification of SHG sources in the mouse brain using a multimodal imaging technique combining SHG and multiplex coherent anti Stokes Raman scattering (CARS) spectroscopy. We performed multimodal imaging in two different regions, the surface and dentate gyrus of the brain tissue. For the brain surface, the SHG signal was recognized through CARS spectrum analysis, indicating its origin in collagen. In the dentate gyrus, CARS images did not unveil corresponding molecular origins; however, morphologically, the SHG signal likely originated from Rootletin within neurons.Overall, Multimodal imaging approach to molecular identification of SHG has the potential to contribute to a comprehensive understanding of the molecular and structural features of the mouse brain. These findings advance labelfree imaging techniques and have implications for brain tissue analysis and functional mapping research.