Ch-NCCD: chitosan hydrogel loaded with copper nanoclusters and carbon dots as a novel antimicrobial and wound healing agent

Abstract Wound infections, particularly surgical site infections, account for approximately 20% of all healthcare-associated infections and occur in about 2%–5% of surgical patients. Hydrogels are gaining increased prominence as antibacterial and wound healing agents. They possess a soft texture, good biocompatibility, and high water-holding capacity. In this regard, we introduce a novel chitosan (Ch)-based copper nanocluster (Cu NC)–carbon dot combination loaded hydrogel (Ch-NCCD). The Ch-NCCD hydrogel was found to be non-hemolytic against human red blood cells (RBCs) and non-toxic against mammalian cell lines. Scanning electron microscopy analysis revealed that it possesses a rough, fibrous surface with interconnected pores. Furthermore, it exhibits a moderate-to-high swelling ratio that helps it maintain a proper balance between moisture absorption and retention, and is therefore well suited for moderate exudate wounds. The Ch-NCCD hydrogel exhibits prominent antibacterial and antibiofilm activity against pathogenic Pseudomonas aeruginosa PAO1. Membrane permeabilization assay through propidium iodide uptake showed that it compromised the integrity of bacterial cell membrane. Finally, in order to emphasize the real-life utility of Ch-NCCD hydrogel, we have shown that it achieves significant wound closure in male Sprague–Dawley rats within 8 d. However, in order to decipher the underlying wound healing mechanisms of Ch-NCCD, further studies combining biochemical and histological analysis are required.