Exosome membrane-coated nanosystems: Exploring biomedical applications in cancer diagnosis and therapy

Bio-mimicking principles have recently been proposed for the surface functionalization of nanoparticles (NPs). Such a strategy is based on camouflaging the NP surface with functional biomembranes to render superior biocompatibility, interfacial features, immune evasion, and active targeting properties to nanomaterials. In this area of research, cell membranes derived from a plethora of highly optimized cells, such as red blood cells, immune cells, platelets, stem cells, cancer cells, and others, have been the pioneers as coating materials. This biomimetic concept has then been applied to subcellular structures, namely extracellular vesicles and intracellular organelles. Exosomes are a nanosized extracellular vesicle subtype secreted by most cells. These phospholipid bilayer nanovesicles are surface enriched with proteins accounting for their dynamic and prominent roles in immune escape, cell-cell communication, and specific cell uptake. Their intrinsic stability, biocompatibility, reduced immunogenicity and toxicity, and specific cell-targeting features denote an optimal biological nanocarrier for biomedical applications. This review highlights the current clinical applications of exosome membrane-coated nanosystems in cancer diagnosis and therapy. These biomimetic nanosystems have emerged as a promising avenue to provide effective, highly specific, and safer cancer-targeted applications. Finally, challenges hindering their clinical application will be mentioned.