Electrokinetic Enhancement of Membrane Techniques for Efficient Nanoparticle Separation and Enrichment

Separation and preconcentration of colloidal nanoparticles are pivotal in various biomedical applications, notably bioprocessing and biochemical detection. While membrane-based techniques are recognized for their efficiency and versatility, diminishing particle sizes pose challenges such as increased flow resistance, escalated back pressure, and issues with particle retrieval due to adsorption onto membranes. In this study, we introduced an electric field-assisted membrane system, integrating conductive metal-coated membranes. By leveraging the electrokinetic effects from voltage application to the membranes, our system adeptly separated and retrieved nanoparticles even finer than the membrane pores. Experiments with polystyrene nanoparticles demonstrated separation efficiencies surpassing 95% and enrichment factors approaching 1.8 folds within 10 minutes. The pressure drops measured across the membranes were significantly lower than that observed in conventional systems with narrower pore sizes, particularly at elevated flow rates. Moreover, the pressure drop exhibited consistent stability over time, suggesting reduced membrane fouling. This approach offers an energy-efficient, high-throughput method for nanoscale particle separation and enrichment, holding promise for point-of-care diagnostics and progressive biomanufacturing.