Development of poly(vinylidene fluoride) graft random copolymer membrane for antifouling and antimicrobial applications

Biocidal and anti-fouling properties in the same polymeric membranes are important in biomedical field for their capability to protect serious infection and filtration of biological molecules. For this purpose we report random graft copolymer of poly(vinylidene fluoride) (PVDF-graft-poly(tBAEMA-ran-OEGMA, PVBO) membranes showing both antifouling and antibacterial activity. The PVBO copolymer is synthesised using ATRP technique and the polymer membranes are produced by breath figure (PVBO-1) and phase inversion (PVBO-2) techniques. The former shows well-developed hexagonal pores (diameter 15 ± 3.5 nm), and good hydrophilicity (contact angle 41.3°). PVBO-1 membrane exhibits good antifouling property for both lysozyme and BSA solutions. Antimicrobial activity measured from agar diffusion method indicates that PVBO-1 shows a large zone of inhibition in case of gram-negative E coli and gram-positive S. aureus bacteria, whereas PVBO-2 and its HCl treated state (PVBO-3) membranes exhibit only a moderate zone of inhibition. The MBC and MIC values indicate that the synthesized membranes are bactericidal in nature and not bacteriostatic. Live and dead cell assay indicates that PVBO-1 can significantly inhibit growth of bacteria even at high bacteria concentration confirming high antimicrobial activity. MTT assay suggests PVBO-1 is non-cytotoxic to mammalian cells and co-culturing activity result suggests high cellular selectivity of PVBO-1.