Progress, challenges, and prospects of small extracellular vesicles isolation and characterization

Exosomes are nanoparticles that can be secreted by almost all cells into the extracellular space and carry active substances such as nucleic acids, lipids, and proteins and can participate in intercellular signaling. Exosomes are consequently used as a natural medicinal ingredient and can also play a role as carriers of biomarkers and drugs. The heterogeneous nature of exosomes suggests that they have considerable potential for diagnosing and treating multiple diseases. However, standardized methods for exosome isolation are still lacking to ensure the yield, purity, and quality of exosomes, which consequently limits their applications. Therefore, isolation methods that produce exosomes with a high yield, purity, and stability and are supported by standardized characterization techniques need to be further developed. In 2018, the International Society for Extracellular Vesicles released guidelines for the isolation and characterization standards of exosomes, and in this review, we have prepared a comprehensive discussion based on these guidelines that describes the biogenesis of exosomes and the principles, advantages, disadvantages, and application prospects of their isolation techniques to provide basic information for the study of exosomes.