Facile and simple purification method for small extracellular vesicles obtained from a culture medium through cationic particle capture.

Although small extracellular vesicles (sEVs) carry DNA, miRNA, and proteins, and they play an important role in long-distance intercellular communication, their generation and circulation mechanisms are unclear. sEVs can be used as biomarkers for the early diagnosis of diseases (e.g., cancer, Alzheimer's disease, melanoma, and cardiovascular diseases) and as drug delivery carriers to the target tissues. Hence, sEVs are attracting considerable attention from scientists and medical professionals. In the present study, we investigated four different commercially available cationic particles (two silica particles modified with diethylaminopropyl or trimethylaminopropyl groups, and two agarose particles modified with diethylaminopropyl or trimethylaminopropyl groups) for the purification of sEVs obtained from a cell culture medium. All the cationic particles captured the sEVs well. The NaCl concentrations required for elution of the captured sEVs differed for the different cationic particles. sEVs were most efficiently captured by silica particles modified with diethylaminopropyl groups, and they were eluted from these particles using 200 mM NaCl as the elution solution. Because the developed method can be used to easily purify sEVs obtained from a culture medium, it is expected to facilitate the functional analysis of sEVs, as well as early diagnosis and treatment of diseases using sEVs.