Photodynamic-Controllable microneedle composite with Antibacterial, Antioxidant, and angiogenic effects to expedite infected diabetic wound healing

Effective treatment of infected diabetic wound (IDW) requires delivering therapeutic agents to both wound surface and deep layers, as well as improving the wound microenvironment through antibacterial actions, clearing excessive reactive oxygen species (ROS), and promoting vascular regeneration. Here, we present a novel inorganic nanosheet called MnO2/PDA@Cu, consisting of manganese dioxide (MnO2) with copper (Cu) ions loaded on its surface through in-situ polymerization, using polydopamine (PDA) as an intermediate. We then encapsulated the MnO2/PDA@Cu nanosheet into a methacrylated hyaluronic acid (HA) soluble microneedle patch, creating a photodynamic-controllable multifunctional MnO2/PDA@Cu-HA microneedle. We used this microneedle to treat IDWs in a rat full-thickness skin defect model. Results demonstrated that the MnO2/PDA@Cu-HA microneedle effectively delivered therapeutic agents to both wound surface and deep layers, where PDA's photodynamic therapy swiftly combated bacteria under 808 nm near-infrared irradiation. Simultaneously, MnO2 acted as a nanoenzyme, mitigating ROS levels and providing oxygen for wound healing. In addition, the photothermal effect of PDA further facilitated the release of Cu, promoting vascularization. The MnO2/PDA@Cu-HA microneedle significantly accelerated wound closure, re-epithelialization, and collagen deposition, enhancing IDW healing. In conclusion, our synthesized MnO2/PDA@Cu-HA microneedle represents a photodynamic-controllable multifunctional platform for IDW treatment, offering a promising approach for effective wound management.