Highly efficient labelling of extracellular vesicles for enhanced detection on a microfluidic platform

Developing precise extracellular vesicles (EVs) labelling techniques with minimal disturbance is of great importance to the follow-up EVs detection and analysis. However, currently available methods such as using probes to conjugate phospholipids or membrane proteins have certain limitations due to EV steric hindrance, dye aggregation, etc. Here, we present a microfluidic platform to enhance EVs’ labelling efficiency and improve their detection. This platform provides excellent sample throughput and high-efficiency EV labelling at lower label concentrations with an optimized flowing rate. Flow cytometry analysis (FCM) and cellular uptake results show that EV labelling by utilizing this platform possesses the merits of a higher labelling efficiency with 64.1% relative improvement than conventional co-incubation method and a lower background noise. Moreover, this technique maintains EVs’ size, morphology and biological activities. After the recipient cells uptake the EVs treated by the microfluidic platform, the spatial and temporal distribution of EVs in the cells are clearly observed. These results demonstrate that our method holds great potential in efficient labelling of EVs, which is essential to subsequent EV quantification and analysis.