Reactive oxygen species-responsive polydopamine-PtCuTe nanoparticle-loaded microneedle system for promoting the healing of infected skin wounds

Nanozymes, known for their high efficiency in scavenging reactive oxygen species (ROS), have received significant attention in promoting the healing of infected wounds. Herein, we reported a novel multifunctional PDAPtCuTe nanozyme with excellent ROS scavenging, antibacterial, pro-angiogenic, anti-inflammatory, and immune regulatory properties. It was loaded onto microneedles (PTPP-MN) for treating infected wounds. In vitro experiments demonstrated its ability to scavenge ROS and exhibit antioxidant properties. Compared to PT-MN (11.03 +/- 3.37 %) and PTP-MN (42.30 +/- 2.60 %), the ROS scavenging rate of PTPP-MN reached 63.63 +/- 4.42 %. The microneedle exhibits good biocompatibility, stimulating fibroblast migration, endothelial angiogenesis, and M2 macrophage polarization. Additionally, it effectively eliminates ROS and provides antioxidant effects while inhibiting the viability of S. aureus and E. coli. Animal experiments showed that the PTPP-MN group achieved near-complete re-epithelialization by the third day compared to other groups. Histological observations revealed that the PTPP-MN group exhibited enhanced granulation tissue formation, epithelial regeneration, and angiogenesis. After PTPP-MN treatment, the local immune response shifted from a pro-inflammatory state to a pro-regenerative state. Our results indicate that PTPP-MN holds great promise for infected wound healing with reduced scar formation.