Immobilization of polybia-MPI by allyl glycidyl ether based brush chemistry to generate a novel antimicrobial surface

Significant efforts towards the covalent immobilization of antimicrobial peptides (AMPs) on biomaterial surfaces are under way to render implantable biodevices with antimicrobial functionalities. Towards this aim, we studied the potential and effectiveness of a novel AMP candidate, polybia-MPI (Pmpi), for immobilization on a silicon substrate using allyl glycidyl ether (AGE) based polymerization chemistry. A statistical Design of Experiment (DoE) platform was developed to quantitatively understand the effects of different immobilization parameters on the final tethered peptide surface concentration. Our platform demonstrates efficient tethering of Pmpi up to ∼10 μg cm^-2 on silicon wafers. Concentration dependent antimicrobial activities of the 'AGE-Pmpi'-tethered surfaces were observed, where a 70% reduction in bacterial colonies was achieved at a Pmpi surface concentration of 4.47 μg cm^-2. The 'AGE-Pmpi'-tethered surfaces retained their antibacterial property after 3 days of incubation in artificial urine, and a 4-fold reduction in biofilm formation was also evident, as determined by ellipsometry. FESEM and ATP leakage assay showed that the immobilized Pmpi compromised bacterial membrane integrity but showed negligible cytotoxicity against human red blood cells.