Figure 4.

Engineering approaches in the modification of EVs can be categorized into four categories: (A) Coding and noncoding oligonucleotides can be introduced into cells through genetic engineering. Their genetic changes can impact the expression of different nucleic acid expressions in the EVs’ cargo. (B) Metabolic labeling is used for introducing non-native moieties into cells. In this technique, metabolite replicas are integrated into cell biosynthesis. (C) Exogenous materials can be introduced to the cells and indirectly load the secreting EVs. (D) Direct EV modification is to permeabilize the vesicle membrane to enable the active loading of EVs. The vesicle membrane itself can potentially be the site of chemical reactions.