Fig. 1.

Targeting and biodistribution/PK analysis strategies of exosome therapeutics. Targeting of exosomes to specific organs or cells could be achieved via modification of the composition of exosomal membrane proteins including tetraspanins and integrins. Exosomal surface engineering by displaying targeting peptides conjugated with exosomal membrane-associated domains such as lysosome-associated membrane glycoprotein 2b (Lamp2b) or C1C2 domain of lactadherin (LA) is another approach for active tissue targeting. Both glycan and lipid compositions of exosomal membrane also contribute to the biodistribution of administered exosomes. Biodistribution/PK analysis of administered exosomes can be conducted via various exosome labeling methods (i.e., bioluminescence, fluorescence, and radio isotope-labeling methods)