A biomimetic urchin-like photothermal nanoplatform for the efficient eradication of Streptococcus mutans and biofilm dispersion

BackgroundDental caries, primarily driven by Streptococcus mutans (S. mutans) biofilms, remains a formidable clinical challenge due to the protective extracellular polymeric substance (EPS) matrix and the limited efficacy of conventional antibiotics.MethodsTo address this, we report a biomimetic photothermal nanoplatform (FWA NPs) featuring a hierarchical, urchin-like multi-spiked architecture, synthesized via the co-assembly of ferrocene-tryptophan conjugates and in situ biomineralized gold nanoparticles.ResultsBenefiting from this unique topological structure, FWA NPs maximize interfacial interactions with bacterial membranes and exhibit enhanced near-infrared absorption, achieving a remarkable photothermal conversion efficiency of 54.4%. Under 808 nm near-infrared (NIR) irradiation, this rapid and localized heat generation induced efficient eradication of S. mutans, which manifested as a dramatic reduction in bacterial colonies from ~107 to ~105 CFU/mL and irreversible membrane damage characterized by massive surface wrinkling, localized collapse, and membrane rupture. Additionally, FWA NPs reduced the survival rate of S. mutans biofilms to approximately 10%, Crucially, FWA NPs demonstrated excellent biocompatibility with a hemolysis rate of approximately 1% for red blood cells and a relative survival rate of 90% for normal cells.ConclusionBy synergistically integrating topological advantages with highly efficient energy conversion, this rationally designed nanoplatform offers a highly effective, non-antibiotic therapeutic paradigm for combating biofilm-associated oral infections and mitigating the global threat of antimicrobial resistance.