Metal‐Phenolic Network with Pd Nanoparticle Nodes Synergizes Oxidase‐Like and Photothermal Properties to Eradicate Oral Polymicrobial Biofilm‐Associated Infections

Abstract Designing an effective treatment strategy to combat oral diseases caused by complex polymicrobial biofilms remains a great challenge. Herein, a series of metal‐phenolic network with Pd nanoparticle nodes using polyphenols as stabilizers and reducing agents is constructed. Among them, sulfonated lignin‐Pd (SLS‐Pd) with ultrafine size palladium nanoparticles and broadband near infrared absorption exhibit excellent oxidase‐like activity and stable photothermal effect. In vitro experiments demonstrate that the superoxide radical generated by SLS‐Pd oxidase‐like activity exhibits selective antibacterial effects, while its photothermal effect induced hyperthermia exhibits potent antifungal properties. This difference is further elucidated by RNA‐sequencing analysis and all‐atom simulation. Moreover, the SLS‐Pd‐mediated synergistic antimicrobial system exhibits remarkable efficacy in combating various biofilms and polymicrobial biofilms. By establishing a root canal model and an oropharyngeal candidiasis model, the feasibility of the synergistic antimicrobial system in treating oral biofilm‐related infections is further validated. This system provides a promising therapeutic approach for polymicrobial biofilm‐associated infections in the oral cavity.