Methods for the extraction and RNA profiling of exosomes

Figure 3 Electron microscopy analysis of exosomes isolated from HeLa cell culture media with the Total exosome isolation reagent. A: Representative image of the unlabeled exosome; B: Exosome immunolabeled with anti-CD63 followed by 10 nm protein A gold nanoparticles; C: Exosome immunolabeled with anti-CD81 followed by 10 nm protein A gold nanoparticles. For immunolabelling, exosome samples were precipitated undiluted at room temperature for 15 min to grids. Next, blocking with 0.5% bovine serum albumin was performed for 10 min. Labeling with anti-CD63 and anti-CD81 antibodies was carried out for 30 min. Following washing steps, Prot A Au were added and incubated for 15 min. After subsequent phosphate-buffered saline and water wash steps, embedding in 0.3% Uranyl acetate in methyl cellulose was finally performed, followed by electron microscop analysis of exosomes.