Mechanical And Biological Behavior Of Osteoblasts Grown On Titanium Alloy Substrate With Titanium Coating

At present,bone replacement is the most effective way to solve bone diseases.Titanium alloy has been widely used in biomedicine,because its surface first directly interacts with the tissue cells in the implanted environment.Therefore,the surface properties of materials are closely related to their biological effects.In this dissertation,pure titanium(Ti)particles are sprayed onto the titanium alloy substrate(Ti-6Al-4V)by atmospheric and vacuum spraying,with the thickness of 300?m and800 ?m,respectively,surface morphology of Ti coating samples are characterized using optical microscope,white light interferometer,scanning electron microscope and X-ray energy dispersive spectrometer.Surface of Ti coated titanium alloy with thickness of 800 ?m and 300 ?m is irregular,multi-stage holes,honeycomb shape,smooth edge,uniform,more like a three-dimensional environment,while the control group(0 ?m)relatively has smooth surface and a large number of undulating micro planes.Murine embryonic osteoblast precursor cells(MC3T3-E1)is used as cellular model and incubated on the surface of the samples to detect the mechanical and biological behavior of the cells,including: 1)fluorescence staining: the proliferation ability of MC3T3-E1 increased with the increase of coating thickness;2)proliferation ability and cytotoxicity of MC3T3-E1 cells cultured for 1,2,3,5 and 7 days detected by MTT method: the proliferation ability of MC3T3-E1 increases gradually with the increase of coating thickness,and the cytotoxicity of samples decreases gradually with the increase of coating thickness;3)Morphology of MC3T3-E1 cells observed by scanning electron microscope: with the increase of coating thickness,cell extends its filopodia to catch attachement from “3D” environment and promotes cell-cell contact;4)alizarin red staining detecting the mineralization of osteoblasts: the degree of osteoblast differentiation of MC3T3-E1 gradually increased with the increase of coating thickness;5)apoptosis of osteoblasts was detected by flow cytometry Results:under the same culture time,the apoptosis rate of MC3T3-E1 decreased with the increase of coating thickness;6)expression of bone differentiation related proteins of MC3T3-E1 detected by Western blot;coating thickness can effectively promote the osteogenic differentiation and related protein expression of MC3T3-E1.In this dissertation,titanium coating with various thickness has great impact on the mechanical and biological behavior of osteoblasts,including adhesion,proliferation and differentiation.The implant surface with higher surface roughness and porosity form many small concave or convex planes,providing more favorable attachment sites,for cell to adhere,extend and grow.Surface roughness increase the contact area between implant and bone tissue,promoting the biochemical reaction and bone integration process.The coating samples and coating treatment methods used in this dissertation improve the design and research of hip replacement prosthesis,and the designed series of experiments play a significant role in promoting the biocompatibility of hip replacement prosthesis in animals.