Extracellular Vesicles-Based Biological Macromolecule Delivery Systems: Biogenesis, Characterization, and Emerging Clinical Applications.
Extracellular vesicles (EVs) are nanoscale membrane-bound structures that play a pivotal role in intercellular communication by transporting bioactive molecules, including proteins, lipids, nucleic acids, and organelles, between cells. Originating from the endosomal pathway, EVs reflect the physiological and pathological status of their parent cells and participate in a broad range of biological processes, such as immune regulation, tissue regeneration, and disease progression. This review provides a comprehensive overview of EVs' biology, covering their biogenesis, biochemical composition, isolation strategies, and characterization methodologies. Recent advances in quantitative, qualitative, and single-vesicle analytical techniques are discussed, highlighting both their advantages and technical limitations. Emphasis is placed on the functional roles of EVs in cancer, cardiovascular diseases, autoimmune disorders, intestinal fibrosis, and neural repair, with a focus on their contributions to disease pathogenesis, biomarker discovery, and therapeutic resistance. Furthermore, emerging strategies employing both natural and engineered EVs as therapeutic delivery platforms are examined. Special attention is given to EVs-integrated hydrogel systems designed to improve bioavailability, enhance retention at target sites, and enable controlled therapeutic release. Despite their considerable therapeutic potential, several challenges remain, including the need for standardized isolation protocols, scalable production, management of vesicle heterogeneity, and successful clinical translation. Overall, this review highlights the multifaceted biological significance of EVs and underscores their increasing potential as diagnostic biomarkers and next-generation therapeutic platforms across a wide range of disease conditions.