Dual-functional antimicrobial coating based on the combination of zwitterionic and quaternary ammonium cation from rosin acid

Treatment of implant-associated infection is becoming more challenging, especially when bacterial biofilms form on the surface of implants. To address the challenge of biofilm infection, developing dual-functional antimicrobial coatings (antimicrobial and antifouling) to combat bacterial biofilm infection are superior to those based on a single modality due to avoiding the adverse effects arising from the latter. In this work, we reported an effective dual-functional coating based on the use of synthetic terpolymers, which combined dopamine, zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and maleopimaric acid quaternary ammonium cation (MPA-N+). The modified surfaces were characterized by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), X-ray spectroscopy (XPS) and water contact angle measurements. The bactericidal efficacies of dual-functional coating were demonstrated by 1.00, 1.09 and 0.94 log reduction of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, Pseudomonas aeruginosa, respectively, and effectively inhibited pathogenic biofilm formation. Moreover, the dual-function coating reduced protein and platelet absorption, while showing minimal cytotoxicity to the mammalian cells. Notably, an in vivo implantation model showed that the dual-functional coating eradicated the pathogenic biofilm from the implants, preventing host tissue damage and inflammation. Taken together, this dual-functional coating displayed great therapeutic potential in treating the formidable clinic problems caused by pathogenic biofilm and the accompanying inflammation.