Urinary exosome isolation using multiple cycles of centrifugation

다국어 초록 (Multilingual Abstract)

Exosomes have great potential for non-invasive diagnostics and therapeutics because of their capacity in facilitating communication between cells and drug delivery. Exosomes are produced in cells and discharged into the extracellular milieu as they circulate throughout the system. Hence, they can be found in biofluids such as blood and urine. Ultracentrifugation is a standard method for isolating exosomes that use high-speed centrifugation, i.e. 100,000×g, to pellet exosomes. However, the exosome integrity can be compromised by repetitive high-speed centrifugation, which damages the vesicles. Our present study employed low-speed centrifugation, i.e. 40,000×g, to isolate exosomes from urine samples. The method required four cycles of centrifugation to remove non-exosomal proteins based on the gel electrophoresis results. Exosomal proteins like CD63 and TSG101 corresponded to the antibodies in Western blotting, confirming the existence of exosomes. Dynamic light scattering profiles suggested that the average diameter of the isolated pellets was 50 to 200 nm, which is the size range of exosomes. All characterization methods indicate that the urinary exosome isolation using lower speed centrifugation was feasible. Further research with a larger group of subjects is needed to assess the reproducibility of the method.