Visualization strategies of extracellular vesicles: Illuminating the invisible ‘dust’ in theranostics

Extracellular vesicles (EVs), lipid bilayer vesicles with diameters of 30-150 nm derived from nearly all cell types, were once dismissed as “platelet dust” but are now recognized as key mediators of intercellular communication, playing vital roles in both physiological and pathophysiological processes. However, the clinical applications of EVs in theranostics remain limited by the challenge of effectively visualizing them at high resolution both in vitro and in vivo , primarily due to their nanoscale size. To address this limitation, researchers worldwide are developing innovative methods for labeling and visualizing EVs, aiming to unlock their full potential in optimized theranostic applications. This review provides a comprehensive overview of current strategies for EV labeling across various experimental settings and highlights their promising theranostic applications of diverse diseases.