Photoactive carbon quantum dots-incorporated injectable hydrogel for synergistic photodynamic antibacterial activity and wound healing

Chronic wound infection poses a clinical threat, as bacterial presence and a prolonged inflammatory phase hinder the normal wound healing process. Photodynamic therapy (PDT) emerges as an effective strategy, demonstrating potent antibacterial activity and healing efficacy compared with conventional strategies. In the present study, carbon quantum dots (CQDs) are prepared as photosensitizers via a hydrothermal approach. The therapeutic efficiency is further improved by incorporating CQDs into an injectable hydrogel (OG) composed of oxidized sodium alginate and gelatin. SEM morphological analysis and FTIR functional group characterization validate the successful incorporation of CQDs into the hydrogel matrix. In vitro cytotoxicity evaluation and scratch assay reveal minimal cytotoxicity, enhanced fibroblast cell proliferation and migration in the CQD-OG hydrogel group under light irradiation. This activity is mediated by photoactivation of CQDs, which upregulates ERK signaling and promotes re-epithelization. Further, in vivo studies confirm that CQD-OG hydrogel shows accelerated wound closure, accompanied by significant collagen deposition and epithelial regeneration. The hydrogel not only promotes tissue regeneration but also mitigates the inflammatory response, as demonstrated by immunofluorescence staining for IL-6 and TNF-α. Therefore, the CQD-OG hydrogel, with excellent antibacterial activity and wound healing properties, represents a potent therapeutic material for chronic wound management.