A trifunctional coating for biofilm prevention: integrating antifouling, photothermal killing, and quorum sensing interference

Bacterial biofilm-associated infections pose a significant challenge in biomedical fields, especially in the context of medical devices and implants, where conventional treatments often fail to combat mature biofilms. To overcome this limitation, an antibiofilm coating was developed, incorporating three functional components: carbon nanoparticles derived from candle soot (CS), hydrophilic and pH-responsive copolymer brushes of 2-hydroxyethyl methacrylate (HEMA) and 3-(acrylamido)-phenylboronic acid (APBA), and natural quorum sensing inhibitors (QSIs). The carbon nanostructure of the CS substrate provides inherent photothermal conversion properties, while its high surface area facilitates efficient chemical functionalization. The copolymer design strategically incorporates hydrophilic poly(HEMA) domains that form bacteria-repellent hydration layers, alongside APBA moieties that covalently bind plant-derived QSIs (quercetin or baicalein) through pH-sensitive boronate ester linkages. This combination of components enables the coating to suppress biofilm formation via three synergistic mechanisms: bacterial adhesion is initially inhibited by hydration barriers, surface-bound pathogens are subsequently eradicated through photothermal conversion upon near-infrared activation, and the release of QSIs triggered by the acidic microenvironment disrupts biofilm maturation. The coating demonstrated sustained antibiofilm efficacy against both Pseudomonas aeruginosa and Staphylococcus aureus , while preserving mammalian cell viability and substrate compatibility across various biomedical materials. By integrating physical barriers, thermal ablation, and quorum sensing interference through precise material engineering, this coating offers a promising solution for preventing biofilm-associated infections in clinical settings.