Skin-Adhesive Antibacterial Hydrogel Loaded with Biosynthesized CuS Nanoparticles for NIR Laser-Induced Wound Healing

The multidrug-resistant bacterial infection is a slow-moving pandemic due to the ineffectiveness of traditional antibiotics in treating such diseases. Photothermal therapy (PTT) is a successful alternative treatment approach that eliminates bacterial infections without harming healthy tissue. Here, we developed a one-pot biosynthetic method for generating CuS nanoparticles as a photothermal agent (PTA) and incorporated them into a tannic acid cross-linked oxidized carboxymethyl cellulose/gelatin composite hydrogel (CuS@TG-OC). The synthesis process utilized soapnut extract as a stabilizing and capping agent to produce hydrophilic CuS nanoparticles. The CuS@TG-OC demonstrated increased antibacterial activity as a result of a mild photothermal effect and regulated Cu²⁺ ion release when exposed to an 808 near-infrared laser. Under laser irradiation, CuS@TG-OC and TG-OC hydrogels demonstrated no toxicity against the NIH3T3 cell line. The CuS@TG-OC+NIR treatment reduced the survival rate of bacterial strains Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) to 8% and 3%, respectively. Additionally, the CuS@TG-OC hydrogel showed cell migration during the scratch assay investigation. Overall, the designed biocompatible hydrogel could be an ideal dressing to inhibit infection, in turn, speeding up the healing process.