Three-dimensional Plotting Of Element Doping Compositing Calcium Phosphate Scaffolds And Their Cytobiological Properties

Bioactive calcium phosphate scaffold playes an important role in bone repair due to its excellent biocompatibility and osteogenesis,it could not only provide mechanical support,but also be considered as a necessary carrier for cell adhesion,proliferation and differentiation.However,it is difficult to take a precise control in terms of the pore structure,pore size and connectivity through traditional fabricating methods,the application of bioactive calcium phosphate scaffolds is restricted in bone repair.Three-dimensional(3D)plotting technique as a rapid prototyping method could effectively solve this problem.On the other hand,this technique was not quite ready for the fabrication of calcium phosphate scaffold,for one,how to construct calcium phosphate scaffold with a high solid phase content using 3D plotting remained a problem.In the meanwhile,3D plotting composite scaffolds modified through elements doping were fabricated to obtain better physicochemical and biological properties.Therefore,this thesis explores the preparation methods of element doped 3D plotting composite scaffolds aiming to get bone repair scaffolds with better physicochemical and biological properties.Mg-whitlockite(Mg-WH)was prepared by methods of direct synthesis techniques and template fabrication.Li doped β-tricalcium phosphate(Li-β-TCP),β-TCP and hydroxyapatite(HA)were fabricated through chemical precipitation method.These materials were used as the raw materials of 3D plotting composite scaffolds.mBMSCs and HUVECs were selected as model cells,a series of tests were conducted to evaluate the biological properties of Mg-WH,and the results indicated that Mg-WH promoted the proliferation of mBMSCs,improved the ALP activity,and showed good biocompatibility and osteogenesis.Besides,it could also enhance the vascularization of HUVECs in vitro effectively.Using 3D plotting rapid prototyping technology,3D plotting Mg-WH compositing of HA scaffolds(Mg-BCP)were successfully fabricated.The pore size was set as 200 μm,and the scaffold exhibited a uniform pore structure distribution and high interconnectivity.Mg-BCP exhibited excellent mechanical properties,and showed the great potential to be used in bone restoration with good mechanical properties.hBMSCs were selected as model cells,a series of tests were conducted to explore the biological properties of Mg-BCP,and the results indicated Mg-BCP could improve the adhesion,spreading and migration of hBMSCs,promote the proliferation of hBMSCs,and significantly up-regulate expression level of osteogenesis genes.Through 3D plotting rapid prototyping technology,we successfully fabricated 3D plotting Li-β-TCP compositing of HA scaffolds(Li-BCP),the pore size set as 200 μm,besides,the scaffold exhibited completely interconnected pore structure and uniform pores arrangement.mBMSCs were selected as model cells,a series of tests were conducted to explore the biological performances of Li-BCP,and the results indicated that Li-BCP improved the adhesion,spreading and migration of mBMSCs,promoted the proliferation of mBMSCs,and significantly up-regulated expression level of osteogenesis genes,possessed better biocompatibility.Moreover,the molecular mechanism of Li-BCP with better osteogenesis ability was studied by differential gene selecting,GO gathering of differential genes and KEGG gathering of differential genes.In the end,a possible molecular mechanism was presented,the existence of Li ions in Li-BCP scaffolds activated the Wnt signaling pathway compared to BCP scaffolds.