Isolation of exosomes by differential centrifugation: Theoretical analysis of a commonly used protocol.

Exosomes, small (40-100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for "fixed-angle" rotors.