Polydopamine hydrogel loaded with curcumin-Ag⁺ in alleviating radiation damage in rat submandibular glands and its antibacterial properties analysis

Objective: To synthesize composite hydrogels loaded with curcumin (Cur)-Ag + using polydopamine (PDA) hydrogel, and to investigate their effect on mitigating radiation-induced damage to salivary gland cells, as well as the synergistic antibacterial effect of Cur and Ag⁺ in the composite hydrogels. Methods: The synthesis of omposite hydrogels loaded with Cur-Ag⁺ and characterization observation were performed. Different concentrations of Cur and composite hydrogels loaded with varying concentrations of Cur-Ag⁺ were co-cultured with human nasopharyngeal carcinoma squamous cells (5-8F cells) and primary submandibular gland cells of SD rats.Cell viability was assessed by cell counting kit-8 (CCK-8) assay. Composite hydrogels loaded with different concentrations of Cur-Ag⁺ were incubated with SD rat submandibular gland primary cells and exposed to different doses of X-ray irradiation (0 Gy, 5 Gy, 10 Gy, 15 Gy) using an electron linear accelerator. The cell viability of each group was evaluated using the CCK-8 assay 72 hours later. PDA glue and various concentrations of composite hydrogels were co-cultured with Escherichia coli and Staphylococcus aureus, and the bacterial growth curve was monitored over 12 hours. Bacteriostasis on AGAR plates was observed after 48 hours. The growth of biofilm was assessed after co- culturing different concentrations of Cur and Ag⁺ with the two types of bacteria for 24 hours. Results: The composite hydrogels exhibited favorable biocompatibility at the experimental concentrations. After incubation for 72 hours, the activity of primary submandibular gland cells was above 80%, and demonstrated a certain cytotoxic effect against tumor cells. After 5 Gy, 10 Gy, 15 Gy irradiation, the activity of primary submandibular gland cells of rats after co-incubation with complex hydrogel could be increased by 30% compared with the untreated pure irradiation group. The concentration of Ag⁺ in the medium was kept constant at 0.1 μg/ mL, and the inhibitory effect of biofilm growth was gradually enhanced with the increase of Cur concentration. The growth curve and plate antibacterial results also showed obvious synergistic antibacterial effect. Conclusion: PDA composite hydrogels loaded with CUR-Ag⁺ can effectively reduce the radiation-induced damage to salivary gland cells. Among the composite hydrogels, the combined application of Cur and Ag⁺ demonstrates enhanced synergistic antibacterial properties.