Exosomes are small extracellular vesicles, 30-150 nm in diameter, which have been determined to play a crucial role in extracellular signaling. They have been observed in both prokaryotic and eukaryotic organisms, meaning they are incredibly widely spread in nature. Exosomes bud off from their parent cells in a sealed package, taking the properties of their parent cell walls with them and encasing many intracellular components.