Quantitative Analysis of Extracellular Vesicle Uptake and Fusion with Recipient Cells

In precision medicine, extracellular vesicles (EVs) are promising intracellular drug delivery vehicles. The development of a quantitative analysis approach will provide valuable information from the perspective of cell biology and system design for drug delivery. Previous studies have reported quantitative methods to analyze the relative uptake or fusion of EVs to recipient cells. However, relatively few methods have enabled the simultaneous evaluation of the "number" of EVs taken up by recipient cells and those that fuse with cellular membranes. In this study, we report a simple quantitative method based on the NanoBiT system to quantify the uptake and fusion of small and large EVs (sEVs and lEVs, respectively). We assessed the abundance of these two subtypes of EVs and determined that lEVs may be more effective vehicles for transporting cargo to recipient cells. The results also indicated that both sEVs and lEVs have very low fusogenic activity, which can be improved in the presence of a fusogenic protein.