Metal–phenolic nanozyme based microneedle patch with antibacterial and antioxidant for infected wound healing

Chronic bacterial-infected wound healing is becoming increasingly severe, with high rates of mortality and disability, owing to bacterial film, excessive accumulation of reactive oxygen species (ROS), inflammatory, and traditional therapeutics with poor drug permeability. Herin, a functional Zn-gallic acid nanozyme (Zn-NM) with excellent antibacterial and antioxidant capacity was incorporated with a gelatin-based microneedle patch (Zn-NM@MN) to achieve transdermal and sustained release of the drug at the infected wound site. The Zn-NM displayed the concentration-dependent antibacterial capacity, and 250 μg/mL of Zn-NM simultaneously possessed excellent antibacterial (89.36 ± 0.95 % for Escherichia coli, 92.44 ± 11.03 % for Staphylococcus aureus, and 95.03 ± 1.06 % for Methicillin-resistant Staphylococcus aureus), antioxidant properties and negligible cytotoxicity. After that, Zn-NM@MN could transdermal the epidermis or biofilm to sustain the release of Zn-NM for 3 h (release of 80 % drug). Systematic tissue regeneration assessment on rats’ infected full-thickness skin wounds demonstrated an enhanced wound healing rate. Zn-NM@MN could efficiently kill the bacteria (about 85 %), alleviate oxidant stress, reduce bacterial-induced inflammation, and promote vascular regeneration. This synergetic therapy strategy will pave the way for treating complicated infection wounds.