Technologies for Visualization and Tracking of Extracellular Vesicles

Extracellular vesicles (EVs) are intercellular communicators that can deliver important biological molecules to recipient cells to participate in the regulation of pathophysiological processes. In recent years, EVs have been used as drug carriers owing to their biosafety and natural transport properties. However, the limited methods available for EV visualization and tracking have hindered in-depth studies of the biological behaviors and applications of EVs. Owing to ultrasmall size limitations, dynamic process requirements, and biological activities, labeling technology should have high spatial resolution, time resolution, and biosafety. Previous studies have attempted to trace EVs both in vitro and in vivo. However, most labeling and tracing imaging of EVs is still aimed at a single component of EVs without specificity or efficiency. Moreover, few super-resolution imaging platforms have been developed for the dedicated and dynamic tracking of EVs. Accordingly, multicomponent labeling and dynamic tracking may provide a promising approach for the visualization and tracking of EVs. With the development of novel methods for the visualization and tracking of EVs, research progress on the mechanisms and drug delivery applications of EVs is expected to facilitate important discoveries in the future.