Comparative Study On The Degradability And Osteogenic Ability Of Silicon-based And Boron-based Bioactive Glasses

Objective: This study through the high temperature melting-quenched the preparation of silicon and boron based bioactive glass,the research of two kinds of bioactive glass in vitro degradation of performance,in vitro of osteoblasts osteogenesis function expression,the influence of material implanted animal observation and degradation and osteogenesis ability,explore two materials in animals degradation performance and suitability of bone regeneration.Methods: According to whether the bioactive glass contains boron,the experimental materials were divided into two groups: The Si BG control group and BBG Boron based bioactive glass(BBG)experimental group were prepared by X-ray diffraction(X-ray Diffraction,XRD)and Electron scanning(SEM)were used to detect the chemical composition and microscopic morphology of the materials,and the materials were soaked in a Simulated body fluid(SBF).The chemical composition,morphology and in vitro bioactivity of the materials were detected by X-ray diffraction(XRD)and electron microscopy(SEM).The weight loss rate of the bioactive glass and the p H value of the immersion solution were also detected to characterize the bioactive glass degradation performance in vitro.The bioactive glass extract was co-cultured with osteoblastic precursor cells.The cytotoxicity of the material and the effect of the material on the proliferation of osteoblasts were detected by CCK-8 method.The Alkaline phosphatase(Alkaline phosphatase)was used to detect the cytotoxicity of the material and the effect of the material on the proliferation of osteoblasts.ALP assay kit was used to detect the effect of materials on the differentiation ability of Mouse embryo osteoblast precursor cells(MC3T3-E1).ALP staining and Alizarin red staining were used to observe the differentiation and extracellular matrix mineralization ability of the cells.Using 3 d printing method construct bionic porous bioactive glass scaffolds,through microscopic CT(Micro-CT)and optical microscope detection bracket on the microstructure and porosity of the stent rabbit bone defect of femoral condyle,the postoperative4 weeks,12 weeks after implantation of X-ray observation materials,and put to death animals,take the general view is healing of postoperative femoral specimens observation,The femur specimens 12 weeks after implantation were stained by hard histology to observe the degradation of the material in vivo and the formation of new bone around it.Result: The results show that the two kinds of bioactive glass powders have similar particle size(< 50μm)and micromorphology.XRD shows that most of the materials are amorphous.After 30 days of simulated immersion in vitro,the weight loss rate of Si BG was 6.98%,and the weight loss rate of BBG was52.3% because the boron element replaced part of silicon element and degraded faster.With the increase of soaking time,the p H values of simulated body fluids all increased slowly,but BBG was faster than Si BG.After soaking for 1 week,the p H value of BBG was 8.8,and that of Si BG BBG was 8.2.XRD after immersion showed more polycrystalline states and HA peaks.In vitro degradation of Sibg and BBG showed that both could be converted to Hydroxyapatite(HA)by degradation.The in vitro cytotoxicity test showed that both materials had good biocompatibility and safety in vitro.Cell proliferation,ALP activity test,ALP staining and alizarin red staining showed that BBG could promote the proliferation and differentiation of osteoblasts more than Si BG.The porosity of the 3D-printed bioactive glass scaffold is BBG 55.31±1.60% and Si BG 54.36±1.74%,which meets the requirements of modern porous biological materials.Postoperative general view showed that the implantation position of the two groups of materials was good and there was no obvious inflammatory reaction.The X-ray results showed that the interface between the implant materials and the bone defect was blurred gradually with the increase of the implant time,but the boron base was more blurred than the silicon base.Implantation experiments of femoral condyle bone defects showed that BBG degrades faster than Si BG 12 weeks after implantation,and induces more new bone formation around it.BBG has better biodegradation and bone regeneration adaptation.Conclusion: By using boron element to replace part of silicon element in silicon,boron based bioactive glass has better biological activity than silicon-based bioactive glass,better in vivo and in vitro degradation performance and bone regeneration ability fitment,which provides a new direction and theoretical basis for the research and development of modern biomaterials and clinical transformation.