In the late 1960s, Bonucci and Anderson first reported finding small, secreted extracellular vesicles in bone cells. Over the next 20 years, through the combined use of electron microscopy, ultracentrifugation, and functional studies, other types of cells including cancer cells and immature red blood cells were also found to secrete extracellular vesicles with great biological significance, and this field has grown substantially.
There are two main types of extracellular vesicles. The bigger submicron-sized ones are called microvesicles while those that are between 30–150 nm in diameter are collectively referred to as exosomes. More specifically, exosomes are a type of nanometer-sized extracellular vesicles that originate through budding from the plasma membrane and endosome membrane. They contain a variety of cargo, including nucleic acids, lipids, and proteins and express transmembrane proteins and receptors that facilitate intracellular communications.READ MORE