Chemical characterization of extracellular vesicles of mesenchymal stromal cells: TOF-SIMS and BCARS approach

Abstract

Paracrine functions of mesenchymal stem (stromal) cells (MSCs) rely, at least partly, on membrane-bound extracellular vesicles (EVs) with rich composition of lipids, nucleic acids and signaling proteins. Elucidation the underlying chemistry could potentially lead to MSCs-free therapy. However, the secretome of MSCs (EVs’ composition) is non-static and depends on many other factors including surrounding cells and medium. Thus, the research techniques must be able to provide not only bulk but microscopy-scale data within a reasonable time frame. Two of these label-free techniques are subject of this work toward the question of chemical composition of the EVs.

High resolution imaging and analysis of extracellular vesicles using mass spectral imaging and machine learning

“…Using Spectrometry mode, high‐resolution spectral data can be collected over a larger, non‐overlapping sample area (200 µm) and used to improve assignments of high spatial resolution data. ToF‐SIMS has previously been used to examine EVs, but only using spectrometry mode and averaging mass spectra (Aybush et al., 2021 ; Marzec et al., 2022 ). To the best of our knowledge ToF‐SIMS mass spectral imaging of EVs at this spatial resolution, has not yet been reported.…”