Photothermal Nanozyme-Encapsulating Microneedles for Synergistic Treatment of Infected Wounds

Photothermal therapy (PTT) is widely used in wound healing because it produces heat under near-infrared irradiation, eliminating bacterial infections. However, excessive production of reactive oxygen species (ROS) occurs during PTT, which causes oxidative stress damage. In this study, a nanozyme, PDA-MnO2 (PM), is synthesized and encapsulated in the needle tip layer of a bi-layer GelMA microneedle patch (PbMP), which has excellent mechanical properties and can easily penetrate the skin. In a study involving an SD rat wound model infected with S. aureus, the PbMP significantly accelerated the healing process of bacterially challenged wounds, resulting in better blood vessel growth, cell proliferation, and collagen biosynthesis than other wound dressings. The experiment shows that the PM nanoparticles in PbMP improve photothermal conversion efficiency and activate SOD and CAT, resulting in an efficient cascade enzyme reaction system to eliminate ROS during the PTT process. This study describes a highly effective nanozyme hydrogel microneedle platform with photothermal synergistic antibacterial effects on wound healing.