A Non-Centrifugation Method to Concentrate and Purify Extracellular Vesicles Using Superabsorbent Polymer Followed by...

Extracellular vesicles (EVs) can be isolated and purified from cell cultures and biofluids using different methodologies. Here, we explored a novel EV isolation approach by combining superabsorbent polymers (SAP) in a dialysis membrane with size exclusion chromatography (SEC) to achieve high concentration and purity of EVs without the use of ultracentrifugation (UC). Suspension HEK293 cells transfected with CD63 coupled with Thermo Luciferase were used to quantify the EV yield and purity. The 500 mL conditioned medium volume was initially reduced by pressure ultrafiltration, followed by UC, SAP or a centrifugal filter unit (CFU). Using either of these methods, the EVs were concentrated to a final volume of approximately 1 mL, with retained functionality. The yield, quantified by luciferase activity, was highest with UC (70%-80%), followed by SAP (60%-70%) and CFU (50%-60%). Further purification of the EVs was performed by iodixanol density cushion (IDC) or SEC (Sepharose CL-2B or 6B, in either 10 or 20 mL columns). Although the IDC and Sepharose CL-2B (10 mL) achieved the highest yields, the purity was slightly higher (30%) with IDC. In conclusion, combining SAP concentration with CL-2B SEC is an alternative and efficient way to isolate EVs without using UC.