Quorum Quenching-Mediated Biofilm Mitigation on Functionalized Ultrafiltration Membranes via Atom Transfer Radical Polymerization

Abstract

Quorum sensing (QS) critically affects biofilm formation during membrane filtration, which can be manipulated for membrane biofouling mitigation. This study demonstrates a quorum quenching strategy for combating membrane biofouling by functionalizing poly(vinylidene fluoride) (PVDF) membranes via atom transfer radical polymerization of a QS inhibitor, vanillin. Poly(vanillin) brushes are successfully grafted on the membrane surface, which is verified by extensive membrane characterization. The effective biofilm inhibition ability and mitigation mechanism of poly(vanillin) brushes are evaluated by analyzing the QS-related gene expression and acyl-homoserine lactone (AHL) signal molecule concentrations. We show that poly(vanillin) brushes can inhibit the bacterial QS system and decrease the AHL concentration to mitigate membrane biofouling. In dynamic filtration experiments, the vanillin-grafted PVDF membrane exhibits a 50% increase in stable flux compared to that of the pristine PVDF membrane. Our results provide an alternate strategy for mitigating membrane biofouling by regulating the bacterial QS system via inhibitor-functionalized membranes.