Recent engineering advances of EVs for compounds, nucleic acids, and TCM delivery

Extracellular vesicles (EVs) are phospholipid bilayer nano-vesicles that were originally identified to deliver signals for intercellular communications. Based on the dynamic contents including proteins, nucleic acids and metabolites, EVs have been developed into diagnostic and therapeutic fields including cardiovascular diseases, neurological disorders and infectious diseases. A growing number of investigations revealed that EVs are also powerful carriers of loaded compounds and nucleic acids as enhanced treatments. Herein, we summarized the recent engineering advances related to three major issues when applying EVs in drug delivery systems: EVs isolation, drug loading strategies and targeting delivery approaches. Moreover, current applications of traditional Chinese medicine (TCM), in composition or compound form, are searched and listed as unique combinations with EVs. Further, we discuss emerging challenges and consider future directions of drug-loading EVs in therapeutic opportunities. This review discusses pros and cons of collecting, drug loading and delivery strategies of EVs as delivery systems, and highlights the promising combination with traditional Chinese medicine to help us advance its clinical application.