Figure 7.

Different methods of EV engineering and their applications. EVs are small membrane-bound vesicles that can be engineered to modify their surface molecules, cargo contents or targeting specificity. Exosome engineering can be achieved by three main approaches: (a) genetic engineering, (b) surface modification, and (c) cargo loading. (a) Genetic engineering involves manipulating the genetic information of exosome-secreting cells using viral vectors, CRISPR-Cas9 system or plasmid transfection of specific gene fragments. This can result in the synthesis of specific proteins, peptides or nucleic acids that can be incorporated into EVs. For instance, EVs can be engineered to express fluorescent proteins, therapeutic genes or immunostimulatory molecules. (b) Surface modification involves attaching biological or chemical molecules to the surface of EVs using covalent or non-covalent bonds. This can alter the biophysical properties, stability or targeting ability of EVs. For example, EVs can be modified with proteins, antibodies, lipids, aptamers, peptides or antigens that can enhance their binding affinity, specificity or immunogenicity to target cells or tissues. (c) Cargo loading involves introducing exogenous molecules into the lumen of EVs using physical or chemical treatments. This can increase the functional diversity and efficacy of EVs. For instance, EVs can be loaded with RNA, nanomaterials, drugs, cytokines or gaseous molecules that can modulate gene expression, imaging contrast, drug delivery, inflammation or vasodilation in target cells or tissues, EGF epidermal growth factor, EVs extracellular vesicles, FGF fibroblast growth factor, VEGF vascular endothelial growth factor, TGF-β transforming growth factor-beta, IFN-γ interferon-gamma