Fig. 3.

The common strategies of exosome engineering. a The integration of multiple basic isolation techniques is a common and efficient method to extract high-purity and high-yield exosomes. b The modified strategies comprise biological, immunological, physical, and chemical modification. Each strategy has its own strengths and weaknesses. Therefore, combining different modification strategies is recommended. c The common labeling strategies include lipid dyes (DiR/DiD), fluorescent (GFP), and bioluminescent protein (GLuc-lactadherin and GlucB). However, a ‘one size-fits-all’ reporter does not exist yet. The labeling reporter should be selected based on the practical question and available imaging equipment. d The common administration method of engineered exosomes is intravenous injection in both preclinical and clinical trials. e Based on the labeling reporter, the imaging equipment is distinct. The common tracking technique is MRI