TABLE 2.

Exosome modification approaches for targeted delivery.

Approaches	Bioactive ligands/transmembrane proteins	Methods	References
Direct modification
Bioconjugation reaction	CP05	Directly bind to the second extracellular loop of CD63	Gao et al., 2018
	RGE-peptide	Cycloaddition reaction	Jia et al., 2018
	BMSC-specific aptamer	Schiff base reaction	Luo et al., 2019
Hydrophobic insertion	RGD peptide	Incubated in modified medium containing DSPE-PEG-RGD	Wang et al., 2017
Genetic engineering
Non-specific proteins	Lamp2b	T7	Kim et al., 2020
		RAGE-binding peptide	Kim et al., 2021
		tLyp-1-lamp2b	Bai et al., 2020
		HuR	Li Z. et al., 2020
	The tetraspanin superfamily	CD9	Li et al., 2019
		The 2nd extracellular loop of CD63	Duong et al., 2019
		CD63-VEGFC fusion protein	Li B. et al., 2020
		CD63 truncations	Curley et al., 2020
Receptor membrane proteins	PDGFR	Human CD3 and HER2 receptors	Shi et al., 2020
	GPI	Anti-EGFR nanobodies	Kooijmans et al., 2016a
	HER2	DARPin G3	Molavipordanjani et al., 2020
	C1C2 domain of lactadherin	RGD-4C peptide	Tian et al., 2021
		Ag	Bliss et al., 2020