High-performance tracking of bacterial extracellular vesicles in living systems using an aggregation-induced emission luminogen

The nano-sized, membrane-enclosed bacterial extracellular vesicles (BEVs) released by bacteria are now regar-ded as important mediators involved in various physiological and pathological processes of human. To elucidate their roles in bacteria-to-host communication, methods for visualizing and tracking of these nano-vesicles are crucial, but ideal means are lacking currently. In this work, we report the development of a bioprobe, DPASP, for BEV bioimaging with superior performance. DPASP can target BEVs with boosted fluorescence due to its aggregation-induced emission (AIE) attribute, which allows BEV labeling with a high signal-to-background ratio. For BEV imaging, DPASP outperforms the commercial dyes in terms of labeling efficiency, retention time, photostability, and biocompatibility. The applications of DPASP in studying the spatial and temporal distribu-tions of E. coli-derived BEVs within living cells and mice were also demonstrated. The approach developed here provides a valuable tool to better understand the roles of BEVs in health and diseases.