Study On Antibacterial Effect Of Chitosan/Borosilicate Bioglass Composite Scaffold Modified By ZnO Nanoparticles On Bone Regeneration

Objective:Cn/BBG composite bone tissue engineering scaffold was prepared by freeze-drying method,and its surface was modified by nano-ZnO.Finally,a multi-functional bone scaffold was synthesized.To explore its physical and chemical characterization and biological evaluation,and to study the effect of ZnO/Cn/BBG composite scaffold on bone tissue regeneration and antibacterial in New Zealand rabbits in vivo.Methods:1.The most suitable BBG was synthesized by sol-gel method.Chitosan solution was used as curing agent,and Cn/BBG mixed solution was injected into the mold with syringe to prepare Cn/BBG composite scaffold and dried.The micromorphology of the scaffold was observed by SEM and its degradability was evaluated.2.ZnONPs-modified Cn/BBG scaffolds were prepared by hydrothermal method.The micro-morphology of the scaffold was observed by scanning electron microscope and its degradability was evaluated.The antibacterial activity and cytocompatibility of the composite scaffolds were evaluated in vitro.3.The in vivo antibacterial and osteogenic effects of chitosan / borosilicate bioglass composite scaffolds modified by ZnO nanoparticles were evaluated by animal experiments.Results:1.BBG powder was successfully prepared by sol-gel method.From the physical state and characterization characteristics of the finished product,it was found that the BBG powder had suitable pore size,high porosity and good performance.Therefore,it is determined that the BBG powder is suitable for further in vitro and in vivo experiments to explore the antibacterial and bone repair properties.2.The preparation process of ZnONPs array modified Cn/BBG scaffold was completed by combined hydrothermal method.SEM and XRD show that a.Successfully coated with ZnO,two kinds of new organisms of different shapes were covered on the composite scaffold,and the overall coverage was high.b.XRD intuitively verified that the new long material on the surface of ZnO/Cn/BBG composite scaffold is the ZnO plating expected in this study,that is,hydrothermal method can coat Cn/BBG scaffold prepared in this study with zinc oxide,which provides a new idea for the preparation of bone substitute scaffold with both antibacterial and bone repair.3.In the subsequent degradation experiment,we found that the degradation performance of Cn/BBG and ZnO/Cn/BBG was evaluated by soaking them in SBF for 42 days.The degradation rate of Cn/BBG is higher than that of ZnO/Cn/BBG(45% vs 37%);this may be due to the loss of soluble components in the stent during ZnO modification and the covered ZnO nanolayer.4.In the in vitro biological evaluation of ZnO/Cn/BBG composite scaffolds,as expected,the modification of nano-ZnO scaffolds improved the antibacterial effect of Cn/BBG scaffolds.The bacteriostatic zone test showed that zinc oxide had obvious inhibitory zone on Cn/BBG scaffolds,while the scaffolds without zinc oxide had no obvious antibacterial activity.However,zinc oxide shows a certain toxicity,and the toxicity is dose-dependent.The results of dead or alive staining showed that the cells could adhere and spread well on the petri dish under the stimulation of ion dissolution of scaffolds,indicating that ZnO had little effect on biocompatibility.5.The wound was photographed by X-ray after operation,and the results showed that the effect and speed of bone formation of Cn/BBG+ZnO+Sa group was higher than that of Cn/BBG+Sa group,so it was verified that Cn/BBG/ZnO composite scaffold had antibacterial effect.However,it is smaller than that of Cn/BBG group,indicating that even if ZnO is added to the infected bone defect,it will affect the osteogenic effect of BBG.The results of HE staining on the experimental specimens of tibia showed that the samples of Cn/BBG/ZnO group were significantly different.It is speculated that the addition of zinc oxide affects normal bone formation,the mechanism is unknown,but there are a lot of connective tissue,cartilage tissue and bone trabeculae,and few inflammatory cells.The results showed that the ZnO coating did not affect the promoting effect of BBG,and the composite scaffold had both antibacterial and bone repair effects.Conclusion:1.ZnO/Cn/BBG composite scaffold was successfully prepared in this experiment,and it was verified in vitro that the composite scaffold had good biodegradability,antibacterial properties and certain biocompatibility.2.Animal experiments show that ZnO/Cn/BBG composite scaffolds have better antibacterial properties,and pure Cn/BBG composite scaffolds have better osteogenic properties.These results show that the proposed ZnO/Cn/BBG composite scaffold has great potential in bone tissue engineering in terms of antibacterial and osteogenic promotion.