Gallium Nanostructure-Based Microneedle Patch for Multidrug-Resistant Bacterial Wound Healing: Enhanced Metal Release and NIR Photothermal Effect

Bacterial infections, especially caused by multidrug-resistant bacteria, pose a big challenge to the healthcare system. As a group of historic agents, metals with broad-spectrum antibacterial activity are regarded as promising alternatives to tackle antibiotic resistance. Among them, gallium ions have presented encouraging antibacterial effects in research and preclinic studies. However, utilization of gallium ions has difficulty in achieving high targeting and long-term effectiveness. With the renaissance of liquid metal, here, a novel and facile antibacterial gallium nanostructure is proposed in which polydopamine-modified gallium nanocore serves as an ion reservoir for enhanced metal ion release and the surface also permits secondary reaction, allowing for in situ formation of Ag nanoparticles to improve the antibacterial property, ROS generation, and photothermal performance. Notably, ≈100% bacterial killing efficacy can be achieved when combined with NIR laser irradiation. The in vivo treatment results of methicillin-resistant Staphylococcus aureus (MRSA)-infected mice demonstrate that the microneedle patch loaded with nanoparticles exhibits outstanding bacterial elimination and inflammation alleviation, and promotes angiogenesis and collagen deposition, further accelerating wound healing. This gallium-based nanostructure offers an effective nanoplatform for antibacterial treatments and combinatory strategies, which holds significant promise for refractory multidrug-resistant bacteria and related infections.