Exosome characterization by Raman Spectroscopy and SPRi

Exosomes are nanoscaled membrane vesicles released by multiple cell types under both physiological and pathological conditions. Together with microparticles, exosomes are considered interesting cargoes for bioactive molecules useful in the intercellular paracrine communication. Their remarkable potentialities in diagnostics and therapeutic treatment of multiple complex diseases such as degenerative diseases of permanent tissues (i.e. central nervous system and muscles) make their deep characterization urgent. LABION is currently working at the biochemical characterization of extracellular vesicles released from cultured mesenchymal stem cells by Raman spectroscopy and of circulating exosomes involved in neurodegenerative diseases by SPRi. immagine-x-pagina-labion - Raman spectroscopy is an interesting new approach for vesicle characterization as it allows the evaluation of their overall chemical composition from a tiny volume of sample avoiding vesicle labeling. We propose the use of Raman spectroscopy both as rapid quality check tool of vesicles to be used for in vitro or in vivo experiments and as biochemical characterization method.

One of Labion team’s ongoing projects is aimed at the characterization of vesicles isolated by ultracentrifugation from the conditioned medium of human mesenchymal stem cells cultured as monolayer in vitro in serum-deprived conditions. Preliminary results presented during the last ISEV meetings demonstrate the ability of the method to successfully detect the main constituents of the isolated vesicles.

- SPRi (Surface Plasmon Resonance imaging) is an analytical technique able to detect variations in the mass adsorbed on top of a gold–coated chip, occurring in a layer of about 200 nm from the surface, as a result of interaction between probe molecules immobilized on the chip and capture target molecules.

We propose the use of  SPRi to facilitate exosomes applied research, allowing the study of the interactions between exosomes and biomolecules. Taking advantage of SPRi technology, we aim to simultaneously detect several markers on exosomes’ membrane with high sensitivity using the mass of the membrane as a source of amplification of the signal.