Photothermally Triggered Silk Fibroin Microneedles with Coordinated Gallic Acid-Iron Networks for Synergistic Infected Burn Wound Therapy

Infected burn wounds remain a formidable clinical challenge due to persistent oxidative stress, bacterial infection, and dysregulated inflammation. Herein, a multifunctional microneedle (MN) patch is engineered through the integration of gallic acid-iron coordination networks (GFe) onto silk fibroin microspheres (SFMSs). The resulting GFe@SFMSs are encapsulated into a dissolvable MN array, enabling direct intradermal delivery and sequential therapeutic release. Upon nearinfrared irradiation, the patch exhibits rapid and potent photothermal antibacterial activity (>99% inhibition against E. coli and S. aureus). The pH-responsive dissociation of the metal-phenolic network facilitates sustained release of gallic acid and Fe ions, conferring durable antioxidant, anti-inflammatory, and chemodynamic effects. Simultaneously, the progressive degradation of SFMSs can activate endogenous regenerative pathways, thereby promoting collagen synthesis and angiogenesis. In a murine infected burn model, the MN patch significantly accelerates wound closure, reduces pro-inflammatory cytokines (TNF-α, IL-6), and enhances tissue remodeling. This work presents a synergistic and spatiotemporally programmable strategy for infected burn healing through the combination of photothermal, chemodynamic, antioxidant, and regenerative functions.