Cu²⁺/Zn²⁺ "Antimicrobial Chamber" with Self-Enhanced Photothermal Activity Supports Infected Wound Healing

Wound healing of drug-resistant bacterial infection is a major challenge in clinical practice, and existing treatments suffer from the drawbacks of high dosage, low efficiency, and insufficient biosafety. Herein, we coated ultrasmall copper sulfide nanoparticles (CuS NPs) into zeolitic imidazolate framework-8 (ZIF-8) and modified them with polydopamine (PDA) to obtain CuS@ZIF-8@PDA NPs for bacterial infection wound treatment. Due to the presence of CuS and the degradability of ZIF-8, CuS@ZIF-8@PDA NPs can continuously release Cu²⁺ and Zn²⁺ in a slightly acidic environment under near-infrared (NIR) irradiation. Furthermore, the introduction of PDA endows it with an excellent photothermal property. The synergistic effect of dual ions/photothermal enables it to effectively eradicate Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Moreover, in vivo experimental results confirm that released Cu²⁺ and Zn²⁺ can promote epithelial regeneration, thereby accelerating wound healing. In the bacterially infected mouse model, CuS@ZIF-8@PDA NPs exhibit excellent synergistic antimicrobial and wound healing effects, while having no toxic side effects on major organs. The study of the dual-ion/photothermal synergistic antibacterial strategy based on CuS@ZIF-8@PDA NPs provides a new insight into bacterial infection wound repair.