Surface modification of silicone elastomer with rosin acid-based quaternary ammonium salt for antimicrobial and biocompatible properties

Abstract Despite advanced sterilized and aseptic techniques, biomaterial-associated infections are still posing a great threat to human life. Therefore, constructing antimicrobial coating that exerts potent antimicrobial activity combined with low cytotoxicity is of great significance. Herein, an antimicrobial coating on the surface of silicone elastomer (PDMS) has been successful constructed, which based on maleopimaric acid quaternary ammonium cation (MPA-N+). The surface morphology and chemical composition of modified PDMS (PDMS-g-MPA-N+) were confirmed by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS). The PDMS-g-MPA-N+ possess excellent antimicrobial activity against both Gram-positive bacterial (Staphylococcus aureus) and Gram-negative bacterial (Escherichia coli, Pseudomonas aeruginosa) strains. In addition, confocal laser scanning microscopy imaging demonstrated that it also can effectively inhibit bacterial biofilm formation over 5 days. Most importantly, PDMS-g-MPA-N+ exhibited excellent biocompatibility, which induced no significant hemolysis and cytotoxicity toward mammalian cells. The study demonstrated that the silicone elastomer surface grafted with MPA-N+ enabled the incorporation of a renewable biomass to effectively combat bacteria and biofilm formation for biomedical applications.