Advanced Exosome Isolation through Electrophoretic Oscillation-Assisted Tangent-Flow Ultrafiltration with a PVDF-Fiber-Coated SiNx Nanofilter.

Abstract

This study introduces a comprehensive approach to enhancing SiN_x nanofilters for exosome isolation from bovine milk using the electrophoretic oscillation-assisted tangent-flow ultrafiltration (EPOTF) process. Reinforcing the nanofilter with electro-spun poly(vinylidene fluoride) (PVDF) fibers significantly improved durability under high-pressure conditions, withstanding nearly 2.8 times greater pressures than nonreinforced nanofilters. The PVDF-fiber-coated nanofilters achieved a flow rate of over 70 mL min^-1, compared to just 25 mL min^-1 for nonreinforced nanofilters. A filter housing system with copper electrodes isolated from the solution flow path further enhanced the electrical stability of the entire system, widening the EPO voltage range while reducing the risk of corrosion and contamination. The PVDF-fiber-coated nanofilter with the electrode in a separated housing efficiently prevented clogging and bioparticle agglomeration, maintaining constant filtration performance across various voltages and duty cycles. Biochemical analyses confirmed the high concentration and structural integrity of exosomes isolated at high flow rates. Long-term tests verified the superior performance of PVDF-coated filters, successfully filtering 3400 mL of milk over 24 h. These results demonstrate the potential of these advances for highly efficient exosome isolation while maintaining the integrity and shape of exosomes, offering promise for the future of exosome isolation research.