Carboxymethyl Chitosan/Sodium Alginate Hydrogels With Polydopamine Coatings For Infected Wound Healing

ObjectiveThe formation of bacterial biofilms and the existence of drug-resistant bacteria pose challenges for anti-infective treatment.To address the problem of difficult healing of infected wounds,a novel anti-infective and wound-healing-promoting multifunctional hydrogel was constructed.The physicochemical properties,biocompatibility,antibacterial,anti-inflammatory,antioxidant,angiogenic properties,and wound-healing-promoting effects of the material were systematically investigated through in vitro and in vivo experiments,with a view to providing a novel and practical material for the repair of infected wounds.Methods1.Multifunctional CAC/PDA/Cu(H2O2)hydrogel was prepared by rapid deposition of polydopamine(PDA)on CMC/Alg/CaCl2(CAC)hydrogel induced by H2O2/CuSO4.The changes in functional groups,morphological characteristics,and mechanical properties of hydrogels were analyzed.The oxidation and deposition of PDA,swelling rate,and in vitro degradation performance of hydrogel were also evaluated.2.The cytotoxicity and haemocompatibility of the hydrogels were assessed by CCK-8,live/dead cell staining,and hemolysis assays,respectively;The antibacterial properties of hydrogels were evaluated by optical density method,plate colony counting,and bacterial crystal violet staining.The In vitro anti-inflammatory activity was evaluated by enzyme-linked immunosorbent assay(ELISA)and real-time directed reverse transcription assay(RT-qPCR).The antioxidant activity of hydrogels in vitro was evaluated by reactive oxygen species(ROS)detection and staining of live/dead cells.Scratch test,Transwell test,tube formation test,and RT-qPCR were used to simulate the effect of hydrogel on wound healing and tube performance.3.A model of methicillin-resistant Staphylococcus(MRSA)infected skin defect was established in SD rats.The healing rate of the wound at different time points and histological analysis of the skin and important internal organs were calculated to evaluate the ability and biosafety of hydrogel in promoting the healing of the infected wound.Results1.The CAC/PDA/Cu(H2O2)hydrogels prepared in this study have good morphology,excellent mechanical properties,as well as good biodegradation and swelling properties.2.CAC/PDA/Cu(H2O2)hydrogels have good biocompatibility in vitro and can effectively inhibit the proliferation of bacteria.In vitro anti-inflammatory experiments showed that CAC/PDA/Cu(H2O2)hydrogel could inhibit the expression of inflammatory genes and the production of inflammatory factors.In addition,antioxidant experiments in vitro showed that the hydrogel can also reduce the production of ROS and protect cells against oxidative stress.In addition,in vitro scratch assay,Transwell assay,tube formation assay,and RT-qPCR showed that CAC/PDA/Cu(H2O2)hydrogels could effectively promote HUVEC cell migration and tubule formation3.The infective wound model of SD rats showed that the healing rate of the CAC/PDA/Cu(H2O2)hydrogel group was significantly better than other groups at 7,11,and 14 d.The hydrogel can effectively kill bacteria,promote the formation of collagen in skin tissue,and the healing of infected wounds.Histological staining of important organs showed that the hydrogel has good biosafety in vivo.ConclusionsCAC/PDA/Cu(H2O2)hydrogels have excellent mechanical properties,good morphology,structure and good biodegradability,and swelling performance.The hydrogel has good biosafety in vitro.It can effectively kill bacteria.Inhibit the production of inflammatory factors,reduce the damage of ROS to cells,and promote HUVEC cell migration and tubule formation.In vitro experiments showed that hydrogel can significantly promote the repair of MRSA-infected skin wounds and promote collagen formation.The hydrogel prepared in this study has a simple preparation method and can be used as a potential biomaterial for the repair of infected wounds.