Exosomes are small extracellular vesicles, typically ranging from 30 to 150 nanometers in diameter. They are secreted by a variety of cell types and have been identified in many biological fluids, including blood, urine, and cerebrospinal fluid. Exosomes are formed inside endosomes, which are part of the intracellular trafficking system, and are released into the extracellular space when multivesicular bodies fuse with the plasma membrane.
