Protein determination
The Thermo Scientific™ Pierce™ BCA Protein Assay Kit was used to determined the protein concentrations in each of the exosome samples obtained using the different isolation methods, IP, TEI, and SEC. Bovine Serum Albumin (BSA) in 1% SDS was used as a standard with final concentrations of 2µM, 1µM, 0.5µM, 0.25 µM and 0.125µM. The BCA reagent (50 ml of solution A and 1 ml of solution B) was added into triplicates of exosome containing media from different isolation method. Series of standards and 10 µl of each sample added into a 96-well plate, followed by 190µl of 1% SDS and 200µl of BCA reagent. The plate was incubated for 30 minutes, and then read at wavelength of 562nm. BCA Total Protein Standard Curve is obtained and the protein concentrations were calculated. The Kruskall-Wallis test is performed to assess whether there is a statistically significant differences in medians of protein content in each of the media obtained by different methods.