Extracellular vesicles (EVs) play an essential role in the communication between cells and transport of diagnostically significant molecules. A wide diversity of approaches utilizing different biochemical properties of EVs and a lack of accepted protocols make data interpretation very challenging.
Researchers from the Russian Academy of Sciences discuss the classical and state-of-the-art methods for isolation of EVs, including exosomes, highlighting the advantages and disadvantages of each method. Various characteristics of individual methods, including isolation efficiency, EV yield, properties of isolated EVs, and labor consumption are compared.
A mixed population of vesicles is obtained in most studies of EVs for all used isolation methods. The properties of an analyzed sample should be taken into account when planning an experiment aimed at studying and using these vesicles. The problem of adequate EVs isolation methods still remains; it might not be possible to develop a universal EV isolation method but the available protocols can be used towards solving particular types of problems.
With the wide use of EVs for diagnosis and therapy of various diseases the evaluation of existing methods for EV isolation is one of the key problems in modern biology and medicine.
The principles used for EVs isolation, methods of isolation, and possible areas of their application
The areas of possible application depending on the properties of EVs are indicated for methods suitable for large scale isolation. ∗HFD method was designed for highly diluted samples, for example, urine. UC, ultracentrifugation, sucrose density gradient ultracentrifugation; DG, iodixanol density gradient ultracentrifugation; UF, micro- and ultrafiltration; HFD, hydrostatic dialysis; SEC, size-exclusive chromatography; PEG, EV precipitation with polyethylene glycol and commercial reagents, based on it; protamine, using EV precipitation with protamine; NaAc, using EV precipitation with NaAc; PROSPR, EV isolation via protein precipitation with organic solvent; PEG + DEX, distributive method.