Characterization And Bioactivity Of CoHAp Composite Coatings Prepared From Titanium Surface

Chapter one Preparation and characterization of hydroxyapatite composite coatingsObjective:A new type of composite coating(Co HAp)with good histocompatibility,osteogenesis and antibacterial properties was prepared by adding cobalt ions to hydroxyapatite.In order to understand the surface morphology and characteristics of composite coating.Methods:Hydroxyapatite composite coating with cobalt ions was prepared by sol-gel method.The surface morphology of the coating was observed by scanning electron microscope(SEM).X-ray energy spectrum analyzer(EDS)was used to detect the composition of the coating by Fourier infrared spectroscopy(FTIR).DX1000 X-ray crystal diffractometer(XRD)was used to detect the crystalline state of the coating.The detection range is 20 °-60 ° and the scanning speed is 0.06 °.X-ray photoelectron spectroscopy(XPS)was used to detect the valence of Co HA composite coating.The electronic universal tester detects the bond between the coating and the substrate.The release curve of cobalt ions was obtained by immersing the composite in PBS.The water contact Angle of the two materials was detected and the hydrophilic ability of the two materials was obtained.The biomineralization ability of the composite was studied by immersing the composite in simulated body fluid.Results:A composite coating was prepared on the surface of titanium.It was proved to be a composite coating of hydroxyapatite containing cobalt ion by EDS,FTIR,XRD and electronic universal testing machine.The release curve of cobalt ion was obtained through the release experiment of cobalt ion.Cobalt ions released rapidly in PBS in the first week,and then gradually stabilized.The hydrophilic ability of Co HAp composite coating is better than that of HAp.The simulated body fluid immersion experiment showed that the composite had certain biomineralization ability.The binding force of Co HAp composite coating and titanium substrate was 16.85±1.63 MPa,and that of the control group was 16.75±1.19 MPa,P > 0.05.Conclusion:Co HAp composite coatings were successfully prepared on the surface of titanium by sol-gel method.The coating can meet the tensile strength requirement of the implant.The addition of cobalt ion did not decrease the tensile strength of HAp composite coating.Co HAp is a potential material.Chapter two Bioactivity and antibacterial properties of hydroxyapatite composite coatingObjective: To understand the bioactivity and antibacterial properties of Co HAp composite coating.Methods: With Co HAp as the experimental group and HAp as the control group,the bone histocompatibility and osteogenic activity of the composite were observed by MC3T3-E1 cell adhesion test and proliferation test.The adherent pictures of osteoblasts were obtained by electron microscopy.The optical density values of bone cells in HAp group and cohap group were obtained by optical density detector.The antibacterial properties of the composite were observed by Escherichia coli antibacterial experiment,and HAp was used as the control group.The colony number of the two materials was compared by colony count.Result:MC3T3-E1 cells can grow on the surface of both materials and adhere tightly.The optical density of MC3T3-E1 cells cultured on HAp coating and Co HAp coating for three days was0.199±0.023 and 0.216±0.030,respectively,P=0.619,there was no significant difference.The optical density of HAp group and cohap group was 0.529±0.062 and 0.623±0.070,respectively,P =0.006,the difference was statistically significant.The difference between the two groups was statistically significant.The counts of colonies in HAp group and Co HAp group were 975.21±127.56 and 511.11±74.26,P<0.001.The difference between the two groups was statistically significant.Conclusion:Cohap composite coating has no toxic and side effects on MC3T3-E1 osteoblasts.It has good histocompatibility and promotes the proliferation of osteoblasts.At the same time,the coating also has the effect of anti Escherichia coli.