Mesenchymal stem cells (MSCs) are versatile cells known for their high proliferation capacity and immune system regulatory properties. They can be easily obtained from various tissues, including bone marrow, adipose tissue, synovium, synovial fluid, amniotic fluid, Wharton's jelly, and the umbilical cord. Evidence suggests that the therapeutic effects of MSCs are primarily realized not through their ability to differentiate or their immunomodulatory capabilities but through the secretion of exosomes. These exosomes are soluble paracrine factors that have significantly advanced the field of regenerative medicine.

MSC-derived exosomes play a crucial role in healing damaged tissues by facilitating intercellular communication. They carry a variety of bioactive molecules, including RNA (such as miRNA, mRNA, and lncRNA), peptides, proteins, cytokines, and lipids. In the realm of translational medicine, the potential applications of MSC-derived exosomes are extensive. They show promise in treating cardiovascular and neurological diseases, liver and kidney damage, autoimmune disorders, and dermatological injuries. Additionally, MSC-derived exosomes stand out as effective drug delivery systems due to their natural biocompatibility and ability to cross the blood-brain barrier. Their surfaces can be engineered with biomaterials for targeted drug delivery, allowing RNA molecules, small-molecule drugs, or gene editing systems to be delivered to specific cells.

As a result, MSC-derived exosomes offer a new cell-free therapeutic approach for treating various diseases, minimizing the risks associated with cellular therapy while preserving many of the advantages. This Methods Collection aims to highlight MSC-derived exosomes as potential therapeutic agents, drug delivery systems, and biomarkers for disease diagnosis. Authors are encouraged to submit protocols that focus on these applications.