Pd@Au Nanoframe Hydrogels for Closed-Loop Wound Therapy

Abstract

In this work, a multifunctional Pd@Au nanoframe hydrogel was designed to detect uric acid (UA) for in situ monitoring of wound infection and enhance wound healing by a chemo-photothermal strategy. In acidic conditions, the Pd@Au nanoframe hydrogels show high peroxidase-like activity by catalyzing H₂O₂ to produce reactive oxygen species (ROS) to damage RNAs of bacteria and enhance antibacterial activity. Under Near-infrared (NIR) laser irradiation, the Pd@Au nanoframe hydrogels exhibit photothermal conversion performance; i.e., the color of Pd@Au nanoframe hydrogel solution varies from deep blue (0 s, 25.4 °C) to red (300 s, 50.1 °C) in infrared thermography. After loading the antibacterial mupirocin (M), the as-obtained M Pd@Au nanoframe hydrogels show a maximum cumulative release rate exceeding 90% for mupirocin, as controlled by NIR laser irradiation. In antimicrobial experiments in vitro, M Pd@Au nanoframe hydrogels exhibit NIR laser-driven antibacterial ability; i.e., 98% Escherichia coli are effectively killed in 10 min. After coating rabbit wounds with a UA sensing patch of M Pd@Au nanoframe hydrogels, wound status can be monitored in real time by detecting UA concentration, leading to rapid wound healing in 4 days by a new synergistic effect of chemo-photothermal strategy. This approach successfully confirms a closed-loop strategy, i.e., real-time monitoring the status of a wound and efficiently perform chemo-photothermal wound therapy, for wound healing by combining functional hydrogels, NIR laser irradiation, and pharmaceutical antibacterials.