Antimicrobial and antifouling coating constructed using rosin acid-based quaternary ammonium salt and N-vinylpyrrolidone via RAFT polymerization

Biofilm formation of pathogenic bacteria on the surfaces of implantable biomedical devices limit their applications and effective usage. Current antimicrobial coatings for implantable biomedical devices have significant deficiencies including a lack of long-term activity and biocompatibility. Herein, a dual-functional coating (antifouling and antimicrobial) was constructed using a combination of N-vinylpyrrolidone (NVP) and maleopimaric acid quaternary ammonium cation containing a double bond functionality (GMA-MPA-N+) via surface-initiated reversible addition-fragmentation chain-transfer polymerization. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were used to confirm the successful construction of coating. GMA-MPA-N+ endowed the dual-functional coating with excellent broad-spectrum antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. The biofilm formation on this coating was inhibited for up to 21 days, and protein adsorption and platelet adhesion decreased significantly compared to those on the pristine substrate surfaces. The cytotoxicity assays demonstrated that the coating displayed excellent biocompatibility with the mammalian cells. Notably, the subcutaneous implantation of samples in the rat assay showed the excellent anti infective property of the coating in vivo. Thus, the dual-functional antimicrobial coating exhibited long-term anti-biofilm properties as well as excellent biocompatibility, thereby providing insights into the design of implantable biomedical devices with antimicrobial properties.