Enhanced antibacterial and wound healing efficacy of a novel CQDs@AgNPs@CS-based nanocomposites: A multifunctional approach for advanced wound care

Wound healing, particularly in the presence of bacterial infections, remains a significant challenge in clinical settings. This study explores the synthesis and characterization of carbon quantum dots (CQDs), silver nanoparticles (AgNPs), and chitosan (CS), designated as CQDs@AgNPs@CS nanocomposites. The primary aim is to evaluate its wound healing efficacy and antibacterial activity. An in vivo incisional wound model in mice is utilized alongside in vitro assessments against clinically relevant Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Acinetobacter baumannii, and Klebsiella pneumoniae) bacteria strains. The nanocomposites are characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, zeta potential analysis, and Scanning electron microscopy to confirm its structural integrity and functional properties. Preliminary results indicate that the CQDs@AgNPs@CS nanocomposites significantly enhance wound healing and demonstrate potent antibacterial activity, with minimum bactericidal concentrations and minimum inhibitory concentrations ranging from 0.234 to 7.5 mg/mL. Histological analysis indicates that wounds treated with the CQDs@AgNPs@CS nanocomposites exhibit accelerated re-epithelialization, improved wound repair, and a reduced inflammatory response, as evidenced by decreased neutrophil counts in the skin tissue, compared to untreated wounds and those treated with individual components (CQDs, AgNPs, CS) as well as the CQDs@CS composite. Notably, the CQDs@AgNPs@CS nanocomposites also display impressive antioxidant activity, achieving an 80.21 % radical scavenging capacity against DPPH^•. These findings suggest that CQDs@AgNPs@CS nanocomposites hold great promise for advanced wound care strategies, effectively integrating healing efficacy and infection control into a single formulation.