Interpenetrating polymer network hydrogels with EGCG-MPN and nitric oxide for periodontitis

Injectable hydrogels have made remarkable progress in the treatment of periodontitis. However, an excessively high swelling ratio causes the hydrogels to expand excessively within the periodontal pocket. Uncontrolled swelling within the confined periodontal pocket can exert detrimental pressure on surrounding tissues, leading to poor blood circulation and tissue hypoxia in the periodontal area, and may even exacerbate the inflammatory response. In this study, injectable low-swelling hydrogels with an interpenetrating polymer network structure were designed based on polysaccharides. The hydrogels were formed through the Schiff base reaction between chitosan and oxidized hyaluronic acid, and interpenetration with methacrylated sodium alginate by UV polymerization. A nitric oxide (NO) donor and epigallocatechin gallate (EGCG) were encapsulated in hydrogels to provide synergistic bioactivity. The results indicated that the hydrogels maintained a low swelling ratio in the oral environment, which also effectively inhibited bacterial growth and scavenged reactive oxygen species (ROS) through the synergistic action of NO and EGCG, thereby promoting the repair and regeneration of periodontal tissue. This research provides a new perspective for the application of injectable hydrogels in periodontitis treatment.