FIGURE 3.

A polymeric form of chitosan is necessary to isolate sEVs from biological fluids. (a) Pre‐cleared HEK‐293 CCM (2 ml) was incubated with a final concentration of 50 μg/ml of the acidic formulation of chitosan that was either digested (+) or undigested (‐) with chitosanase (1U/mg of chitosan). Two chitosan types of different polymeric lengths, 60–120 kDa and 141 kDa, were used. Western blot analyses for CD63, CD9, HSC70, FLOT1, and CANX were performed on the isolated material; total cell lysate from MCF‐10A cells was used as a positive control for CANX. (b) NTA analysis of sEVs isolated from HEK‐293 CCM by scUCF or the acidic formulation of chitosan of either 60–120 kDa or 141 kDa, with (+enzyme) or without chitosanase treatment. Particle concentration (particles/ml) is plotted against size (nm) of particles. The mean plus the standard error of the mean (n = 3) is shown