[Progress in extracellular vesicle imaging methods].

Extracellular vesicles (EVs), including exosomes and microvesicles, are lipid bilayer-enclosed nanovesicles secreted by cells. These EVs are important mediators of intercellular communication by serving as vehicles for transfer of proteins, mRNA, miRNA and lipids between cells. Various visualization methods have been established to explore the characteristics of EVs and their role in physiological and pathological processes. The nanoscale size and high heterogeneity of EVs hamper the identification of their biological characteristics and functions. This review presents a comprehensive overview of EV imaging methods in light of the origin, separation and dynamic tracking of EVs, and the advantages and disadvantages of different imaging strategies are discussed. We believe that studies at the levels of single vesicles and single cells will become the frontier of future researches of EVs.