Tailoring the Porosity of Mesoporous Polyphenol Nanoparticles for Enhanced Photothermal Antibacterial Therapy

ABSTRACT

Photothermal therapy offers a promising alternative for treating infected wounds while mitigating antibiotic overuse. However, the limited near‐infrared (NIR) photothermal conversion efficiency of polymeric materials hinders their clinical translation. Herein, we report the synthesis of Mn‐chelated mesoporous poly(L‐DOPA) nanoparticles (Mn‐mDOPA) via polymerization‐induced self‐assembly, where the surfactant/oil ratio and Mn loading are precisely tuned to optimize mesoporosity and photothermal performance. The resulting Mn‐mDOPA nanoparticles exhibit enlarged mesopores (≈28–39 nm) and a high specific surface area (up to 75.4 m ² ·g ^{− 1} ), enabling superior light absorption and heat generation, as confirmed by COMSOL simulations demonstrating a surface‐area–dependent photothermal conversion effect. These structural features endow Mn‐mDOPA with efficient NIR‐triggered bacterial eradication (99.9% for S. aureus and 99.7% for E. coli ) and substantial dark antibacterial activity (> 90%), attributed to the synergistic effects of hyperthermia and mesopore‐mediated bacterial disruption. Moreover, the abundant catechol groups impart potent ROS scavenging capacity, alleviating oxidative stress and protecting wound‐related cells. In a S. aureus‐infected wound model, Mn‐mDOPA effectively suppresses inflammation, promotes angiogenesis, and accelerates wound closure. Collectively, these results highlight Mn‐mDOPA as a multifunctional, antibiotic‐free nanoplatform that integrates enhanced photothermal conversion, intrinsic antibacterial activity, and antioxidant protection, providing a highly promising strategy for localized infection control and wound regeneration.