Wound dressing application of pH-sensitive carbon dots/chitosan hydrogel

Abstract

Monitoring the pH of wounds has been recognized as an essential diagnosis factor during the healing process. This study presents a novel chitosan–carbon dots nanocomposite with dual applications as an antibacterial and pH-sensitive nano-agent for enhancing wound healing and monitoring the pH at the same time. The carbon dots (CDs) were synthesized using ammonium hydrogen citrate under hydrothermal conditions. The chitosan-based nanocomposites with different concentrations of CDs were fabricated through a solvent casting method. After detailed material characterization of the CDs and chitosan/CDs nanocomposites, the antibacterial activities and cell viability were thoroughly investigated against the Staphylococcus aureus bacterial species and L929 fibroblastic cell lines, respectively. The results indicated that the chitosan/CDs nanocomposites were biocompatible and nontoxic with effective antibacterial properties. The mechanical properties of the chitosan/CDs nanocomposite were improved via the addition of the CDs. The results show that the preparation of the chitosan/CDs nanocomposite at a concentration of 1.0 wt% carbon dots possessed the best optical, biological and mechanical characteristics. Furthermore, the results reveal that the proposed chitosan/CDs nanocomposites had outstanding pH-sensitive properties. According to the strong antibacterial properties and nontoxicity, as well as outstanding pH-sensitive nature, the proposed chitosan/CDs nanocomposites, as a smart materiel, have great potential applications in tissue engineering. Furthermore, the optimized ratio of CDs/chitosan nanocomposite was used as an antibacterial wound healing bandage and in vivo experiments were carried out on three groups of rats. The results showed that the CDs/chitosan nanocomposite not only possessed high pH sensitivity, but could also improve the wound healing process due to its antibacterial properties.