Synergistic antibacterial and pro-healing chitosan-nano-CuO/ZnO composite dressing for wound management

Skin wound infections are challenging clinical complications that require dressings with both strong antibacterial activity and wound-healing capabilities. This study aimed to develop a composite wound dressing with potent antibacterial and healing-promoting functions. Using chitosan non-woven fabric (CS) as the matrix, nanometer-sized copper oxide (CuO), zinc oxide (ZnO), and their mixtures were loaded via ultrasonic impregnation to prepare CS + CuO, CS + ZnO, and CS + CuO + ZnO composite dressings. Characterization analysis revealed that the nano-metal oxides were uniformly distributed on the fiber surface, with a positive dose-dependent relationship in loading capacity. All dressings exhibited significantly enhanced antioxidant capacity compared to CS, along with safe and stable ion release profiles, structural stability in PBS, rapid degradation in 0.1% acetic acid, as well as excellent swelling capacity and tensile strength, meeting the fundamental requirements for dressing fabrication. Antibacterial tests demonstrated that the dressings showed no significant inhibition against E. coli but exhibited notable antibacterial activity against S. aureus, MRSA, P. aeruginosa, and K. pneumoniae, with some effects surpassing those of antibiotic controls. The antibacterial performance of composite dressing was generally higher than that of blank CS. The dressings demonstrated good biocompatibility with goat endometrial epithelial cells at a concentration of 500 μg/mL and shortened in vitro clotting time. In a goat full-thickness skin defect model, the dressings promoted epithelial regeneration and collagen deposition, and upregulated the expression of TGF-β1, VEGF, and PDGFB. The results indicate that the CS + CuO + ZnO composite dressing is a safe and effective wound treatment material.