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

Wound infections account for about one-third of all hospital-acquired infections in surgical patients. They are linked to a high mortality rate, causing around 70-80% of related deaths. 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 nanoclusters (Cu NCs)- carbon dots(Cdots) combination loaded hydrogel (Ch-NCCD). Ch-NCCD hydrogel has been found to be non-hemolytic against human RBCs and non-toxic against mammalian cell lines. SEM analysis revealed that it possesses a rough, fibrous surface with interconnected pores. Further it exhibits moderate-to-high swelling ratio that helps it to maintain a proper balance between moisture absorption and retention and is therefore well suited for moderate exudate wounds. Ch-NCCD hydrogel exhibits prominent antibacterial and antibiofilm activity against pathogenic Pseudomonas aeruginosa PAO1. Membrane permeabilization assay through PI uptake showed that it compromised the integrity of bacterial cell membrane. Lastly, 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 days. However, in order to decipher the underlying wound healing mechanims of Ch-NCCD, further studies combining biochemical and histological analysis are required.