| This study is aiming at combining the excellent physical property, good biological activity and specificity of biological molecules of titanium alloy. Anodic oxidation and micro-arc oxidation was first applied on the surface of the titanium alloy; after further being modified by poly-dopamine film (PDA), on one hand, hydroxyapatite (HA) bioactive coating was obtained by using biomimetic mineralization method; then we studied the impact of poly-dopamine induced deposition on the surface of the titanium alloy. On the other hand, we used poly-dopamine as bridge, and modified it with casein phosphopeptide (CPP) that would promote absorption and utilization of calcium, so a dopamine-casein phosphopeptide biological composite film (PDA-CPP) is formed. And using biomimetic mineralization, we prepared HA bioactive coating and investigated the effect of casein phosphopeptide induced deposition on the surface of the titanium alloy. Using field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), contact angle measurement, X-ray photoelectron spectroscopy (XPS), and the total reflection Fourier transform infrared spectroscopy (ATR-FTIR), the surface morphology, phase structure, wettability, and the composition of titanium alloy ingredients before and after modification were systematically characterized. Meanwhile, cytocompatibility was investigated by culturing osteoblasts on the titanium alloy before and after modification. The main results are concluded as follows.(1) Compared with untreated titanium alloy, anodic oxidation and micro-arc oxidation treatment could induce the formation of nanotubes or micron pore structures on the surface of titanium alloy. Further being modified by PDA, a new peak of N element appeared on the XPS spectra, verified the formation of PDA film on the titanium alloy. The water contact angle measurement results showed that the PDA film on both of the surface has hydrophilic properties with water contact angles of48°and54°, respectively.(2) The biomimetic mineralization experiments showed that the PDA film on the titanium alloy after oxidation treatment could significantly promote the formation of HA coating with a dense and regular structure. (3) The titanium alloy after anodic oxidation and micro-arc oxidation treatment was covered by PDA-CPP biological composite films after amidation between PDA and CPP. Meanwhile, the water contact angle measurements showed that the PDA-CPP biological composite film had better hydrophilic properties. Element change of titanium alloy surface can be detected by XPS after the functional assembly, and corresponding chemical groups of PDA-CPP biological composite films appeared on the ATR-FTIR spectrum.(4) Biomimetic experimental results showed that the PDA-CPP biological composite film on titanium alloy after anodizing and micro-arc oxidation treatment can improve the performance of HA mineralization. Comparing to micro-arc oxidation treatment, anodizing oxidation treatment had a better mineralized effect.(5) Osteoblasts cultured in vitro results showed that the PDA-CPP biological composite film on titanium alloy had a better osteoblast cell proliferation and adhesion ability after oxidation treatment compared with the unmodified titanium alloy. This material will find potential applications in clinical medicine. |
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