Multimodal microscopy, by combining fluorescence, harmonic and electron microscopy signals, is therefore of real interest for taking advantage of complementary information and increasing the sensitivity of pathology detection to qualify a complex tissue state.
Ex: Imaging of stimulated Raman scattering (SRS), coherent anti-Stokes Raman scattering (CARS), and two-photon (2P) fluorescence (or autofluorescence). We will thus be able to offer multimodal analysis on a single sample section in order to obtain spatial mapping of molecular compounds of interest, such as CH2 groups for lipid analysis (steatosis assessment) or CH3 for protein analysis.
Technology: Spontaneous Raman microscopy
Uses inelastic scattering of light (Raman effect) to obtain a molecular fingerprint of the sample, providing label-free chemical information.
Unlabelled imaging can be used to characterise histological sections by mapping them without treatment. It is also possible to complete the analysis using immunohistochemistry, multiplex immunoflorescence or histological staining technologies. A holotomography Nanolive and a serial block face imaging (Kratoscope, based on image recording triggered with a sectioning device such as a microtomoe or cryoststat) are available on the MIcroPIcell facility
Imaging by Raman spectroscopy (RAMAN DXR2xi imager, ThermoFisher Scientific): each molecule has a unique spectral signature, determined by the Raman photons emitted after interaction with light. These photons are collected and analysed to provide information on the structure and chemical composition of the sample. We are mapping several thousand spectra on frozen tissue sections just a few microns thick.
Stimulated Raman imaging (SRS_microscope BondXplorer, Lightcore Technologies) complements spontaneous Raman spectroscopy. It can be used to target certain areas of interest in the spectrum in order to image chemical compounds. Acquisitions are therefore faster and can be carried out over larger fields of view.
Anti-Stokes Coherent Raman Scattering (CARS) microscopy provides high-resolution, high-speed, high-sensitivity, non-invasive imaging. It offers the possibility of visualising specific biomolecules without prior labelling.