Fig. 4

Modifications to culture conditions can further reduce exosome carryover to the lower transwell chamber, beyond the physical barrier provided by the transmembrane filter. “Restrictive media” conditions refer to washing cells and adding basal, serum-free (mTeSR) medium to avoid addition of exogenous serum-based exosomes. Nanoparticle Tracking Analysis (NTA) was used to determine the concentration of exosomes isolated following usual culture and passage conditions (a) as compared to concentration of exosomes isolated from cells subjected to restrictive medium conditions (b). Mean values from 5 independent runs are shown ± SD. The restrictive conditions reduced exosome contamination by ~75% compared to cells in normal culture medium conditions (c)