How are exosomes different from other types of extracellular vesicles?

Exosomes and extracellular vesicles are both tiny packages that are released by cells into the surrounding environment. Both play important roles in cell communication by transferring various molecules that they contain from parent cells to recipient cells. The main difference between exosomes and extracellular vesicles lies in their origin and size. Exosomes are a specific type of extracellular vesicle that are formed inside the cells and released when certain compartments within the cell, called endosomes, fuse with the cell's outer membrane. Endosomes are nano-sized particles, typically ranging in size from 30 to 150 nanometers in diameter. Extracellular vesicles refer to the broader category of cell-derived membranes that encompasses all types of vesicles released by cells including exosomes, microvesicles, and apoptotic bodies. Extracellular vesicles can vary in origin and size. They may be released upon cellular activation, under physiological conditions, apoptosis, or senescence. Typical sizes of extracellular vesicles range from 30 nanometers – 5000 nanometers.