Mixed polymer brushes with integrated antibacterial and antifouling properties

[Display omitted] •Mixed polymer brushes with tunable structure.•Integrated antifouling and antibacterial properties.•Long-term anti-bacterial adhesion.•Strong bacterial killing ability. Development of novel materials with dual antibacterial and antifouling functions is important for many bio-applications. In this work, we design and synthesize a series of mixed polymer brushes grafted from silica surface as a new type of antibiofouling and antimicrobial coating, which combine poly(N-hydroxyethyl acrylamide) (polyHEAA) synthesized by atom transfer radical polymerization (SI-ATRP) and cationic poly(trimethylamino) ethyl methacrylate chloride, polyMETAC) synthesized by photoiniferter-mediated polymerization (SI-PIMP). The surface composition, charge and morphology of the resultant mixed polymer brushes are carefully characterized and optimized by tuning ATRP and PIMP initiator ratios. The mixed polymer brushes possess strong bacterial killing ability from polyMETAC chains and high antifouling property from polyHEAA chains. At the optimal conditions, the mixed polyHEAA/polyMETAC brushes exhibit excellent anti-bacterial adhesion property by retaining ultralow cell adhesion of ˜3.0 × 105 cells/cm2 and high contact killing efficiency by killing more than 90% attached bacteria of Escherichia coli and Staphylococcus. Long-term antibacterial performance indicated the cell adhesion was retained at ultralow level of 5 × 105 cells/cm2 even after 72 h exposure to bacteria solution. The results indicate that surface grafting with polyHEAA and polyMETAC can be potentially useful for long-term biomedical and biomaterial applications.