A pH-responsive nanozyme-integrated fibrous biointerface for chemodynamic antibacterial therapy and infected wound healing.

Abstract

Skin wounds are highly susceptible to bacterial invasion, and persistent infection remains a major obstacle to effective tissue repair. Conventional wound dressings often show insufficient antibacterial activity and limited capacity to actively regulate the infected wound microenvironment. Herein, an acid-responsive nanozyme-loaded composite fibrous membrane was developed as a non-antibiotic wound dressing for enhanced chemodynamic antibacterial therapy. Silver nanocubes were encapsulated within zeolitic imidazolate framework-67 to form Ag@ZIF-67 nanozymes, which were subsequently incorporated into electrospun polycaprolactone fibers to obtain Ag@ZIF-67/PCL composite membranes. Under weakly acidic conditions mimicking infected wounds, the ZIF-67 shell underwent microenvironment-triggered decomposition, enabling sustained release of Co2⁺ and Ag⁺. The released Co2⁺ catalyzed the conversion of H₂O₂ into highly toxic hydroxyl radicals through a Fenton-like reaction, while Ag⁺ provided additional broad-spectrum antibacterial activity. Benefiting from this complementary antibacterial mechanism and the extracellular matrix-like fibrous architecture, the Ag@ZIF-67/PCL membrane achieved antibacterial efficiencies exceeding 98% against both Escherichia coli and Staphylococcus aureus after 48 h. Moreover, the composite membrane exhibited favorable cytocompatibility and hemocompatibility, promoted endothelial cell migration, and significantly accelerated the healing of S. aureus-infected wounds in vivo by enhancing re-epithelialization, collagen deposition, and neovascularization. Overall, this study provides a pH-responsive, nanozyme-integrated fibrous membrane with combined antibacterial and pro-regenerative functions, offering a promising strategy for the treatment of bacteria-infected wounds without relying on antibiotics.