Preparation and characterization of a new pH-responsive hydrogel with bacteriostatic properties

To develop a novel wound dressing with multiple functionalities and pH-responsiveness, a combination of quaternary ammonium chitosan (QCS), oxidized dextran grafted with sulfadiazine (Dex-CHO/SD), and tobramycin(TOB) was employed to fabricate the DSTQ hydrogel through Schiff base bonding and hydrogen bonding. The hydrogel formation relied on Schiff base bonding and hydrogen bonding. The morphology, degradation, bacteriostatic, cytocompatibility, and hemocompatibility properties of the hydrogels were analyzed. The results indicated that the 3D pore structure of DSTQ hydrogel could respond to pH drops caused by infections and degrade, facilitating drug release. The inhibition rate of DSTQ hydrogel against Pseudomonas aeruginosa was significantly higher than that of Staphylococcus aureus. DSTQ hydrogel exhibited low toxicity, high biosafety, and cell viability above 95% after three days of co-culture with L929 cells. Additionally, it demonstrated excellent hemocompatibility, with a hemolysis rate below 5%. Furthermore, cells exhibited rapid migration on the material's surface, promoting wound healing. When loaded with growth factors, DSTQ hydrogel demonstrated good anti-inflammatory effects. These findings suggest that DSTQ hydrogel can be an effective wound-dressing option in clinical settings.