Commonly used methods for extracellular vesicles? enrichment: Implications in downstream analyses and use

Extracellular vesicles (EVs) are becoming promising tools for clinical application, either as sources of disease-specific molecular signatures for the unraveling of disease pathophysiology and establishment of novel bio-markers, or as platforms for cell-free nanotherapy. Yet, an unsolved issue is to define standardized techniques for EV isolation allowing data comparison across laboratories worldwide. Considering the difficulties to find this necessary consensus, it has to be stressed out that the outcome of the downstream analysis might be deeply biased by the isolation method, among other variables. Thus, it is crucial that the researcher is aware of the strengths and weaknesses of each method keeping their intended use in mind, and to sufficiently report the methodology details for the results to be comparable and solid. This review aims to present the most widely used EV isolation methods, from the initial differential ultracentrifugation (dUC) to newest approaches.