等离子喷涂TiO_2-CaF_2复合涂层的结构及体外生物矿化能力

Microstructures and In vitro Biomineralization Ability of Plasma-sprayed TiO_2-CaF_2 Composite Coatings

目的等离子喷涂TiO_2涂层是生物惰性材料,不能与骨组织很好地结合,制备TiO_2-CaF_2复合涂层以提高氧化钛涂层的体外生物矿化能力。方法利用等离子喷涂技术在医用Ti合金表面制备TiO_2-CaF_2复合涂层。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和拉曼光谱仪(Raman)对复合涂层的微观结构进行表征,利用接触角仪、三维轮廓仪和电化学工作站考察复合涂层的接触角、表面粗糙度和耐腐蚀性能。采用模拟体液(SBF)浸泡实验考察复合涂层的体外矿化能力。结果 TiO_2和TiO_2-20%CaF_2涂层主要由金红石型TiO_2构成,其中含有少量的锐钛矿型TiO_2成分。20%CaF_2的掺杂会促进金红石型TiO_2的形成。CaF_2的加入可改变TiO_2涂层的表面形貌,表面粗糙度Ra从4.96μm降低至0.94μm,亲水性也得到增强。TiO_2-CaF_2复合涂层在SBF中的耐腐蚀性能也较TiO_2涂层有所提高。经SBF浸泡28 d后,TiO_2-CaF_2复合涂层表面可沉积类骨磷灰石,显示了较好的体外矿化能力,而TiO_2涂层则无此能力。结论 CaF_2的掺杂可使TiO_2涂层的表面粗糙度下降,亲水性增强,耐腐蚀性增强。体外矿化实验结果表明,TiO_2-CaF_2复合涂层表面可沉积类骨磷灰石,显示了较好的生物活性。

Titanium oxide （TiO2） coating is a bioinert material and cannot induce new bone formation at the implant surface. The work aims to enhance in-vitro biomineralization ability of TiO2 coating by preparing TiO2-CaF2 composite coating. TiO2-CaF2 composite coating was deposited on medical titanium alloy by taking advantage of plasma spraying technology. Scanning electron microscopy （SEM）, X-ray diffractometer （XRD） and Raman spectrometer were used to characterize microstructure of the composite coating. Contact angle, surface roughness and corrosion resistance of the coating were measured by contact angle meter, surface profiler and electrochemical workstation, respectively. Simulated body fluid （SBF） immersion test was performed to evaluate in-vitro biomineralization ability of the coating. Phase composition of the coating was mainly rutile, including few anatase. The doping of 20wt% CaF2 could promote formation of rutile TiO2. The addition of CaF2 could change surface morphology of the TiO2 coating, reduce surface roughness （Ra） from 4.96 μm to 0.94 μm, and enhance hydrophily. Corrosion resistance of the TiO2-CaF2 composite coating in SBF was higher than that of TiO2 coating. After being immersed in SBF for 28 days, the surface of TiO2-CaF2 composite coating could induce the bone-like apatite while exhibiting excellent in-vitro biomineralization ability while the TiO2 coating could not. The addition of CaF2 can decrease the surface roughness of TiO2 coating, and enhance the hydrophilicity and corrosion resistance. The bone-like apatite can deposit on the surface of TiO2-CaF2 composite coating, exhibiting excellent in-vitro biomineralization ability.