Research On 3D Printed Multifunctional Bioactive Ceramic Scaffold

Filling of bone repair materials in the bone defect area caused by excision of bone tumor site and external trauma is an effective treatment for bone defects.The performance of bone filling materials directly affects the repair effect of bone defects.Both autogenous bone and allograft bone have certain limitations in the treatment of bone defects,which requires bone fillers to have excellent biological activity,mechanical strength matching with the defect site,controllable biodegradation performance,and appropriate pore structure and size.With the development of clinical application,higher requirements have been put forward for the performance of bone repair scaffolds.On the one hand,the residual tumor cells after the resection of bone tumors may cause the failure of therapeutic effect,so the anti-tumor requirements have been put forward for bone scaffolds.On the other hand,in order to treat bone defects faster and better,excellent bone regeneration and repair ability of bone scaffolds is required.Therefore,in this paper,a multi-functional bioactive ceramic scaffold with anti-tumor performance and excellent bone regeneration and repair ability was manufactured by combining 3D printing technology and impregnation coating technology.The specific research content and results of this paper are summarized as follows:(1)Nano-hydroxyapatite(n-HA)was adsorbed on the surface of the main scaffold doped with magnesia-doped calcium silicate(CSi-Mg),and the CSi-Mg/n-HA composite scaffold was prepared.The experimental results show that different adsorption parameters can be changed to obtain different n-HA adsorption layer thickness(0 μm ～ 20 μm),simulated body fluid immersion experiments on the scaffold,the results show that the mechanical strength of the scaffold has a good retention,three weeks after the compressive strength of 81-91 MPa.At the same time,the simulated humoral solution degradation experiment showed that the scaffold has good biological activity.(2)In order to explore the antitumor performance of the scaffold with n-HA surface coating,this paper conducted a series of experiments to explore the antitumor performance of the scaffold by observing the surface cell morphology of the scaffold and cell apoptosis experiment.The results showed that both the CSi-Mg/n-HA1 scaffold and CSi-Mg/n-HA3 scaffold showed inhibitory effects on the adhesion and number growth of human osteosarcoma cells(MG63).Transwell assay and cell scratch assay demonstrated that the CSi-Mg/n-HA1 and CSi-Mg/n-HA3 scaffolds inhibited the migration of human osteosarcoma cells(MG63).Then,through the cell death staining experiment,cell morphology staining experiment,CCK-8 experiment,alizarin red staining experiment,and the exploration of the expression of ALP,OCN,RUNX2,BSP and other osteogenic genes,We found that the CSi-Mg/n-HA1 scaffolds and CSi-Mg/nHA3 scaffolds had positive guiding effect on the growth of rat bone marrow stem cells,which was conducive to calcium salt deposition,and could promote the repair and growth of bone tissue.(3)Gallium(0wt%,2.5wt%,5.0wt%,7.5wt%)and 10 mol% magnesium were doped into wollastonite ceramics to obtain four bioactive ceramic materials(CSiMg/Ga0,CSi-Mg/Ga2.5,CSi-Mg/Ga5.0,CSi-Mg/Ga7.5).Combined with 3D printing technology,wollatonite ceramic scaffolds doped with gallium and magnesium were prepared and the mechanical properties of four scaffolds were studied.The experimental results show that the scaffold has excellent mechanical properties after sintering at 1120 ℃.(4)The ion release of four scaffolds in Tris solution was investigated.The ion release showed that CSi-Mg/Ga2.5,CSi-Mg/Ga5.0 and CSi-Mg/Ga7.5 scaffolds could release magnesium,calcium and gallium,which had potential synergistic effect of gallium and magnesium on osteogenesis.Degradation performance in simulated body fluids showed that CSi-Mg/Ga5.0 and CSi-Mg/Ga7.5 scaffolds maintained good mechanical properties.We demonstrated that the CSi-Mg/Ga5.0 scaffolds and CSiMg/Ga7.5 scaffolds had better cell activity and osteogenic properties than the CSiMg/Ga0 scaffolds by cell death staining and immunofluorescence staining experiments.In this dissertation,the preparation process and anti-tumor properties of anti-tumor scaffolds were deeply explored.Behind the anti-tumor phenomenon,the internal mechanism of its anti-tumor performance and high mechanical properties was widely discussed.In this dissertation,gallium-magnesium co-doped bioactive scaffolds with gallium-magnesium synergistic osteogenesis were also prepared,which provided a new process technology and solution strategy for the subsequent in-depth exploration and manufacture of bone repair scaffolds with anti-tumor performance and excellent osteogenic performance.It also promoted the further development of customized bone repair scaffolds with multiple functions and different shapes in clinical practice.