Design of Antibacterial Poly(ether sulfone) Membranes via Covalently Attaching Hydrogel Thin Layers Loaded with Ag Nanoparticles.

To inhibit bacteria attachment and the subsequent formation of biofilms on poly(ether sulfone) (PES) membranes, poly(sulfobetaine methacrylate)/poly(sodium acrylate) antibacterial hydrogel thin layers were covalently attached onto the membranes, followed by loading with Ag nanoparticles. In our strategy, double bonds were firstly introduced onto the PES membrane surfaces to provide anchoring sites, and then the hydrogel layers were synthesized on the membrane surfaces via UV light-initiated crosslinking copolymerization. Then, Ag ions were adsorbed into the hydrogel layers and reduced to Ag nanoparticles by sodium borohydride. The amounts of the adsorbed Ag ions were controlled by the mole ratios of carboxylate groups in the hydrogel layers. After attaching the hydrogel layers, a typical 3D porous structure was observed by scanning electron microscopy, and the surface chemical composition variations were characterized by attenuated total reflection-Fourier transform infrared spectroscopy. The live/dead staining, inhibition zone, and the optical degree of co-culture solution demonstrated that the designed surfaces could not only effectively resist bacteria attachment but also kill the surrounding bacteria Escherichia coli and Staphylococcus aureus. It was noteworthy that the strong antibacterial ability could be maintained for more than 5 weeks. Additionally, the excellent hemocompatibility of the modified membranes was confirmed by undetectable plasma protein adsorption, suppressed platelet adhesion, prolonged clotting time, low hemolysis ratio, and suppressed blood-related complement activation. Cell culture tests indicated that the membranes showed no cytotoxicity, but strong anti-cell adhesion properties. The proposed method to fabricate antibacterial hydrogel thin layers has great potential to be widely used to inhibit the formation of biofilms on various biomedical devices.