Extracellular Vesicles: A Review of Their Therapeutic Potentials, Sources, Biodistribution, and Administration Routes.

Extracellular vesicles (EVs) participate in intercellular communication and play an essential role in physiological and pathological processes. In recent years, EVs have garnered significant attention as cell-free therapeutic alternatives, vectors for drug and gene delivery, biomarkers for disease diagnosis and prognosis, vaccine development, and nutraceuticals. The biodistribution of EVs critically influences their efficacy and toxicity. Therefore, this review aims to discuss the main factors influencing the biodistribution of unmodified EVs, highlighting their distribution patterns, advantages, limitations, and applications under different routes of administration. In addition, we provide a comprehensive discussion of the currently available sources of EVs and summarize the current status of the therapeutic potentials of EVs. By optimizing administration routes and selecting appropriate EV sources, we aim to offer valuable insights to enhance the delivery efficiency and therapeutic efficacy of EVs to target tissues.