Carbon Quantum Dots Incorporated Injectable Hydrogel for ROS Mediated Photodynamic Antimicrobial Therapy

Antimicrobial resistance has become a worldwide issue, which reduce the effectiveness of traditional antibiotics due to the development of resistant bacterial strains. The study focuses on the synthesis of sodium alginate/gelatin injectable hydrogel using schiff based crosslinking and incorporated with photosensitive carbon quantum dots (CQDs). The hydrogel facilitates the controlled release of CQDs, which generate reactive oxygen species (ROS) upon irradiated with blue light (470 nm), thereby enhancing the effectiveness of photodynamic antibacterial activity. The hydrogel exhibited the interconnected porous network (50 µm), swelling ratio of 2233% and storage modulus of 620 Pa. The degradation profile of CQD/OSA/GEL was 3.75% slower than OSA/GEL due to the increased crosslinking density. CQD/OSA/GEL hydrogel achieved bactericidal rate of 29% under dark condition and 95% upon exposed with light for 10 minutes against gram‐positive bacteria (Staphylococcus aureus). Similarly, for gram‐negative bacteria (Escherichia coli), the activity rate without light was 26.33% and the percentage is increased to 96.33% upon irradiation. In vitro dark cytotoxicity experiment confirms the biocompatibility of CQD/CQD/GEL, while photoactivation increase the fibroblast proliferation due to controlled generation of ROS and activation of intracellular ERK pathway.