Fig 3. Nanoparticle and protein analysis of MB eluates and DUC concentrates.

Transmission electron micrographs of negatively stained EVs isolated and eluted from magnetic beads (MB) or pelleted by differential ultracentrifugation (DUC) methods from PPP. Scale bars represent 100 nm. The double-layer character of EV membranes could be discerned at increased magnification (insets) (A). Enumeration of nanoparticles in MB eluate and DUC concentrate by NTA (B). Protein levels were quantified using MicroBCA assays. The ratio of nanoparticle concentration to μg protein was plotted as a relative measure of purity (C). Data are expressed as mean ± SEM from three measurements (** p < 0.01, Student’s t-test).