We established a method for the efficient protein loading into extracellular vesicles. FKBP and FRB pair can bind each other in the presence of a small molecule called rapamycin. FKBP and FRB are fused with CD81(EV marker membrane protein) and protein of interest (POI), respectively, so that POIs can be recruited into EVs in the presence of rapamycin. We confirmed this system worked well to load POIs into EVs and functional delivery using EVs coated with VSV-G which significantly facilitate the cytoplasmic cargo delivery.
Plasmids for this system are available through Addgene.