Reusable semi-IPN polymer networks as long-term antibacterial coatings

The current study aimed to develop a reusable antibacterial coating that can be employed for efficient bacterial killing. We synthesized a water-soluble methacrylamide-based copolymer consisting of cationic and hydrophobic groups and coated it onto a glass surface through the formation of semi-interpenetrating polymer networks (semi-IPN) of aminopropyl triethoxysilane and glutaraldehyde. The coated surface was exposed to Gram-negative and Gram-positive bacteria, where the surface exhibited rapid bacterial killing ability within 5-15 min. The substrates displayed a minimal loss of antibacterial activity even after two water rinse cycles. The coatings were able to kill both the bacterial strains even after 5 weeks, suggesting excellent longevity. The surfaces were stable after repeated wiping cycles with 70% IPA using Kim wipes and 5 min sonication in DI water as no bactericidal activity was lost. Thus, a sustainable antibacterial copolymer coating was developed, and it is stable and reusable against bacterial contamination and could be employed as a long-term antibacterial coating.