Synergistic Antibacterial Remineralization: A Bioprocessing-Inspired Single-Step Nanoparticle-Induced Liquid...

Bacterial invasion compromises the inherent reparative capability of dentin, leading to caries progression. Designing an effective strategy to simultaneously restore the dentin structure and combat oral biofilms remains a great challenge. This study presents a single-step biomimetic approach that employs carboxyl-functionalized gold nanoparticles (AuNPs-COOH) as a noncollagenous protein analogue to generate nanoparticle-induced liquid precursor (NILP) for synergistic dentin regeneration and antibacterial therapy. The AuNPs-COOH stabilize amorphous calcium phosphate precursors and induce intrafibrillar mineralization, thereby restoring the hierarchical architecture and mechanical properties of dentin (elastic modulus: 24.42 GPa; hardness: 1.06 GPa), closely matching those of sound dentin (24.84 and 1.15 GPa, respectively) and surpassing conventional polymer-induced remineralization. The remineralized dentin exhibits dual antibacterial functionalities activated by near-infrared (NIR) light: photothermal effect and photodynamic generation of reactive oxygen species. This NIR-activated system significantly inhibits Streptococcus mutans biofilm formation in vitro, reducing biofilm biomass to 10-20% of control levels under both immediate and long-term conditions, and demonstrates robust antibacterial efficacy in vivo. Furthermore, the remineralized dentin exhibits excellent biocompatibility with dental pulp stem cells and minimal systemic toxicity in animal models. The AuNPs-COOH-mediated NILP system thus offers a synergistic strategy for functional dentin regeneration and caries prevention.