NIR-triggered gelatin-based hydrogel for ion-mechanical synergistic antibacterial therapy and infected wound closure

Bacterial infection and impaired wound closure remain the leading causes of refractory cutaneous wound healing disorders, inflicting substantial global morbidity and mortality while exacerbating the crisis of antibacterial resistance. Infected cutaneous wounds present a persistent clinical difficulty, given that bacterial infection and inadequate wound closure exacerbate one another. Here, we constructed a hydrogel platform that integrates antibacterial activity and active wound closure through ion-mechanical coupling. The system combines thermoresponsive, catechol-functionalized network with core-shell nanoparticles consisting of a metal-organic framework shell (MOF) encapsulating a liquid metal core (LM). Under near-infrared (NIR) irradiation, the liquid metal generates heat that triggers network contraction to mechanically close the wound. Simultaneously, sustained release of Zn²⁺ and Ga³⁺ from the nanoparticles provides continuous, antibiotic free antibacterial activity. In a mouse MRSA infected wound model, this hydrogel achieves complete closure within 14 days with improved tissue regeneration. By integrating ion mediated antibacterial action, photothermal bacterial inactivation, and active mechanical contraction in a single platform, this design addresses the intertwined challenges of infection and impaired closure without the compromises of conventional approaches.