Bismuth-Nanosheet-Armed Pristine Silk Nanofiber Dressing for Multimodal Pathogenic Bacteria Eradication and Infected Wound Healing

Traditional antibiotic-based therapies for treating infectious wounds often face challenges in balancing long-term biosafety, promoting wound healing, and effectively eradicating bacteria. Herein, we introduce an innovative "top-down" approach to fabricating one-dimensional (1D) pristine silk nanofibers (SNFs) by the gradual exfoliation of silk fibers, preserving their inherent semi-crystalline structure. These SNFs functioned as a robust template for the in situ growth of two-dimensional (2D) plum blossom-like bismuth nanosheets (BiNS), whose anisotropic morphology enhances bactericidal contact efficiency. The resulting BiNS-equipped SNFs (SNF@Bi) are assembled into membranes (SNFM@Bi) via vacuum filtration, showing superior biocompatibility, photothermal efficiency, and photodynamic activity. Furthermore, the acidic wound microenvironment or near-infrared (NIR) irradiation triggered the release of Bi³⁺, exhibiting nanoenzyme-mediated catalytic activity. This multimodal mechanism allows SNFM@Bi to eliminate over 99% of Staphylococcus aureus and 100% of Escherichia coli by disrupting biofilms, inducing lysis, and causing oxidative damage. In vivo evaluations demonstrated significant bacteria clearance, accelerated angiogenesis, and enhanced collagen deposition, contributing to rapid wound healing without systemic toxicity. Notably, SNFM@Bi detaches spontaneously after healing, avoiding chronic nanomaterial retention risks. This multifunctional antimicrobial platform offers a controllable, effective, and biocompatible therapeutic strategy for antimicrobial dressing design, with potential applications in biomedicine, environmental protection, and public health.

Graphical abstract