General Approach to Engineering Extracellular Vesicles for Biomedical Analysis.

Extracellular vesicles (EVs) are cell-derived nanoscale vesicles that play critical roles in numerous pathophysiological processes. Enrichment and detection of EVs are technically challenging due to the lack of appropriate modification strategies. Herein, we propose a general, facile, and robust approach to engineering EVs by installation of maleimide (Mal) moieties onto EV surfaces based on a hydrophobic insertion strategy. Mal serves as a high-efficiency clickable handle for functionalizing EVs without influencing their structural integrity and biological activity. The Mal-installed EVs were applied into three biomedical applications: (i) labeling with a fluorescent dye for monitoring the EV-mediated cellular communication, (ii) rapid enrichment by magnetic particles (MPs) for high-efficiency EVs isolation, and (iii) conjugation with gold nanoparticles (AuNPs) for Raman detection of the surface components of EVs in situ. This technique would greatly facilitate the applications of EVs in both basic studies and clinical uses.