Antibacterial Effect Study Of Self-Supplying H₂O₂ Modified Nanozyme-Loaded Hydrogel On Root Canal Biofilm

Background:The purpose of root canal treatment is to remove the microorganisms inside the root canal system to promote the healing of the periapical tissue.However,root canal treatment has a certain probability of failure,and the failure of root canal treatment brings unbearable pain to patients and seriously affects patients.from a biological point of view,root canal treatment must eliminate microorganisms and prevent possible reinfection.Unfortunately,the root canal system is anatomically complex,and it is a challenging problem to remove bacteria and biofilms adhering to the canal wall effectively.The use of root canal disinfection drugs has become one of the essential links in root canal treatment.Traditional root canal disinfectants such as sodium hypochlorite（Na Cl O）solution,chlorohexidine（CHX）solution,calcium hydroxide（Ca（OH）₂）paste,and other drugs are the primary means to eliminate and reduce bacterial infection,while These commonly used root canal disinfection drugs have some shortcomings,such as poor antibacterial effect on certain bacteria,possible allergic reactions,poor biological safety.Therefore,it is crucial to develop a new type of root canal disinfection drug.Necessary.Due to the increasing number of nanotechnology and its application in the medical field,especially in the field of antibacterial,its supporting treatment methods are also showing diversity.Therefore,using nanotechnology to develop antibacterial,anti-inflammatory,highly biological Safe root canal disinfection drugs have become possible.Objective:The self-supplying H₂O₂ modified nanozyme was loaded into the hydrogel to synthesize the Fe₃O₄-CaO₂-Hydrogel platform,and its effect on removing biofilm in the root canal was studied through in vitro and in vivo experiments.Methods:1.Self-supplied H₂O₂ modified nanozymes were synthesized by co-precipitation method,and loaded into hydrogel by electric stirring at room temperature to synthesize Fe₃O₄-CaO₂-Hydrogel.2.Characterize the Fe₃O₄-CaO₂-Hydrogel by means of scanning electron microscopy（SEM）,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,and use DPBF probes to detect active oxygen（ROS）release curve.3.Select the optimal concentration of the modified nanozyme in the hydrogel by in vitro cell experiment（CCK-8）and in vitro antibacterial experiment（CFU colony count）.4.The metabolic effects of Fe₃O₄-CaO₂-Hydrogel on root canal biofilm were explored by CFU colony counting,bacterial live/dead staining,MTT method,and crystal violet staining.At the same time,SEM,inductively coupled plasma（ICP）emission spectrometry and the detection of the metabolic activity of exopolysaccharides to observe its effect on the root canal biofilm structure.5.The therapeutic effect of Fe₃O₄-CaO₂-Hydrogel nanohydrogel on root canal infection was evaluated by rat（SD）in vivo experiments.Results:1.The self-supplied H₂O₂ modified nanozyme was successfully loaded in the hydrogel and evenly distributed.The pore size of the hydrogel was appropriate,which provided a good foundation for later tissue repair.At the same time,the release curve of ROS showed that the hydrogel can release ROS slowly and for a long time.2.When the hydrogel is loaded with the modified nanozyme at a concentration of 1.5 mg/ml,the antibacterial rate and biological safety have reached the ideal effect.3.Fe₃O₄-CaO₂-Hydrogel has an excellent effect on removing root canal biofilm.Compared with the control group,the metabolic activity of root canal biofilm treated with Fe₃O₄-CaO₂-Hydrogel decreased to 16.05%,at the same time,the hydrogel not only destroyed the structure of individual bacteria,but also reduced the metabolism of exopolysaccharides in the overall biofilm.4.In vivo experiments show that this hydrogel can prevent tissue damage very well and reduce the local inflammatory response,thereby promoting the accelerated recovery process of the infected site.Conclusions:In this study,the biosafety of the tissue was ensured based on sterilization by introducing the modified nanozyme with the characteristic of self-supplying H₂O₂ into the hydrogel with excellent biocompatibility.Through this design,the nano-platform can release ROS slowly and for a long time,which improves the success rate of root canal treatment by killing bacteria and regulating inflammation and provides a new idea for disinfection in the root canal.