A pH-responsive, multifunctional dressing based on MOF-functionalized chitosan for infected wound repair through macrophage phenotype modulation

Infected wounds pose a substantial clinical challenge worldwide due to the persistent inflammatory and microbial microenvironment, highlighting the urgent need for intelligent wound dressings capable of dynamically responding to pathological changes and promoting tissue repair. Herein, a surface-modification strategy was used to construct the multifunctional composite dressing cs-g@HCA@ZIF-8@DHM by covalently grafting hydrocaffeic acid (HCA) on the surface of chitosan gauze. The HCA-modified surface served as an interfacial template for the in-situ nucleation and growth of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals, followed by adsorption-loading of dihydromyricetin (DHM). The fabricated dressing integrated surface hemocompatibility, significantly accelerated blood clotting, and exhibited potent antibacterial activity (>99% against Escherichia coli and Staphylococcus aureus) in vitro. It also demonstrated superior hemostatic performance in rat models of liver/tail bleeding. The dressing accelerated wound closure (>90% closure by day 12) and attenuated inflammation in infected wound models. Notably, ZIF-8 endowed the dressing with pH-responsive DHM release at the material-bio interface, leading to an anti-inflammatory effect while minimizing side effects. This interfacial engineering approach provides an integrated strategy for developing smart dressings to address challenges in wound healing, ranging from initial hemorrhage to persistent inflammation.