A proton-gated gold nanocluster platform for disrupting biofilm bioenergetics and suppressing virulence in bacterial infections.

Current clinical management of periodontitis, a chronic inflammatory disease driven by dysbiotic biofilms, faces a persistent challenge: biofilm-associated infections remain difficult to eradicate owing to the resilient energy metabolism and high virulence of key pathogens such as Porphyromonas gingivalis. To address this challenge, we developed ultrasmall AHMP-stabilized gold nanoclusters (AHMP@AuNCs) based on a bioenergetics-centered "Metabolic Trap" paradigm. Their sub-2-nm architecture supports bacterial-interior access, while preferential bacterial accumulation may be facilitated by the pyrimidine-mimetic ligand environment, potentially through pyrimidine-associated recognition or uptake processes. A proton-responsive Au-ligand interface undergoes reversible electronic-state modulation, with near-neutral to weakly alkaline intracellular conditions favoring a charge-transfer-associated state. Following bacterial accumulation, AHMP@AuNCs disrupt proton homeostasis and energetic coupling, leading to ATP and NAD depletion, nucleotide metabolic imbalance, secondary oxidative stress, and suppression of T9SS-dependent virulence. Integrated metabolomic and transcriptomic analyses reveal coordinated rewiring of energy, nucleotide, and virulence networks, supporting the "Metabolic Trap" concept. Across oral biofilm models, AHMP@AuNCs inhibit biofilm formation and access internal regions of mature biofilms, disrupting established architecture while showing limited cytotoxicity in the evaluated host-cell models. In experimental periodontitis, local administration preserved epithelial barrier integrity, attenuated inflammation, reduced the P. gingivalis-associated burden, and limited periodontal tissue destruction, with favorable short-term tolerability. This strategy demonstrates that targeting intracellular energy vulnerabilities can achieve antibacterial, antibiofilm, and antivirulence effects against persistent infections.