Photothermally triggered silk fibroin microneedles with coordinated gallic acid–iron networks for synergistic infected burn wound therapy

Abstract

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 in situ 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. Leveraging the relatively weak nature of the coordination bonds, this composite structure exhibits photothermal antibacterial activity (>99% inhibition against E. coli and S. aureus) during the early stage of wound healing, and then gradually degrades in the subsequent phase to release iron ions and gallic acid, 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.