| In this paper, sandblasting, acid etching and anodic-oxidation was used to constructe hierarchical micro-nano porous topography on titanium surface, the composite coating are prepared by using electrophoretic deposition method on the micro-nano-composite structure, the subsequent thermal treatment methods is used to optimize the structure and composition, and to prepare the micro-nano-porous bioactive coating with a high biological activity. The micro-porous nano composite coating surface structure and physico-chemical properties of the different treatments were characterized by scanning electron microscopy (SEM), laser scanning confocal microscope (CLMS), X-ray diffraction (XRD), X-ray energy spectral dispersion meter (EDS), X-ray photoelectron spectroscopy (XPS) and contact angle measurement and electrochemical workstation; After soaking in the SBF, the biomimetic coating are deposited on the surface, and phosphorus surface structure limestone layers were characterized by using SEM, XRD, fourier transform infrared spectroscopy (FT-IR) according to the number, morphology and biological samples form time of apatite layerto evaluate the level of activity.the sample is immersed in the red blood cells in culture tubes, according to the color of the tube and the number of free hemoglobin mass properties of the specimen is used to determine the merits of hemolysis; through the sample and the cell co-culture, the shape of cells were observed by inverted phase contrast microscope and the cell proliferation relative is detected to evaluate the cytotoxicity level of the sample by the use of CCK-8 method.The micron porous structure is prepared on the titanium surface by sandblasting and acid etching method, then the micro-nano composite porous structure is get by anodic-oxidation.the morphology of the sample of the different treatment methods was observed by SEM. with the contrast spray sand and blasted etching process, ANO sample is more suitable for the matrix material of electrophoretic deposition; the tructure of the sample surface with the different parameters were characterized by using SEM, CLMS, XRD. Using the control variable method determines electrophoretic deposition voltage parameters 3V, time parameters lh, the electrolyte concentration Ca(NO3)2:(NH4)2HPO4 equal 10:4, the best ratio of electrolyte species is water. The main phase of the deposition coating is matrix Ti phase and Brushite phase By XRD measurement.the major elements Ti the chemical form corresponding to +4, O compound states corresponding to the-2 price, Ca state corresponds compound+2 price, P compound state corresponds -5 price by XPS measurement. After heat treatment, the coating undergoes a phase change to form a new phase calcium pyrophosphate, the main phase of is the anatase and rutile mixed titanium dioxide the surface structure has been optimized, the surface element content is increased.After soaking SBF, the apatite layer on the surface structure were characterized by using SEM, EDS, XRD, FT-IR; confirmed by SEM and XRD, the morphology and composition phase of the UNTR, SLA and ANO sample is remained unchanged. It can be explained that the samples of sandblasted treatment and sandblasted etching treatment and anodizing treatment did not induce the formation of apatite, and the biological activity is poor; after the UNTR and SLA samples are treated by the electrophoretic deposition, after the three days of soaking SBF, the phosphorus limestone have formatted on the surface of the samples, It can be indicated that the biological activity of the sample is improved after electrophoretic deposition; the ANO electrophoretic deposition samples were soaked in SBF 3 days,and the original appearance is completely covered by the formation of large spherical apatite, with the increase of immersion time, the formation of the apatite is mutual stuffing, the border is increased, the thickness of the apatite layer is increased. It is described that the micro-nano composite porous structure coating has the higher biological activity on the ANO electrophoretically deposited base material.After the heat treatment of anodizing, After the electrophoretic deposition treatment, It can be named the ANO+R+EPD samples, while immersing in SBF for 7 days, the original appearance is completely covered by the formed spherical apatite, compared with the ANO+EPD samples, the diameter of the formed spherical apatite is more smaller, It can be indicated that the titania nanotubes amorphous to crystalline played refining effect on apatite grain, which causes a decrease in the diameter of the spherical apatite; electrophoretic deposition coating is thermally, soaking in SBF for 7 days, spherical apatite is formed attached to the original structure, It is retained the similar original morphology structure. It can be inferred apatite nucleation and growth belong to heterogeneous nucleation, but also It shows that the coating forms a new phase after phase transition, which can not occur dissolution reaction, and can not promote the formation of apatite.Prior to the electrophoretic deposition, the wetting angle of the UNTR, SLA, ANO sample gradually decrease, while the wetting angle of UNTR and SLA sample after electrophoretic deposition is equal to the wetting angle of the ANO sample, It can be indicated that the deposition coating is the hydrophilic material, the wetting angle of the ANO sample after electrophoretic deposition is less than 10°, It belongs to super-hydrophilic material. Roughness and wetting angle of the sample showed the opposite trend, It indicates that the roughness is more larger, the smaller the wetting angle, the better the hydrophilicity. The corrosion resistance of the blasted and anodized titanium samples after electrophoretic deposition is improved, the corrosion current decreased, indicating that the corrosion resistance is improved.The SAEPD is cultured soaked in red blood cells in test tubes, the supernatant of the tubes is presented clear and colorless, cell sink. The measured cell hemolysis rate of 2% is less than 5%, it can be indicated that the sample is no hemolytic; After the SAEPD and L-929 cell are co-cultured for a time, The cell morphology is presented spindle and irregular triangles, the relative value of the cells is greater than 70% by the CCK-8 methods, indicating that the sample is not cytotoxic.In summary, the micro-nano porous composite structure coating is formated by sandblasting etching, anodizing and electrophoretic deposition, which has a higher biological activity, without the cytotoxicity and hemolysis. The samples meet biocompatibility requirements. |
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