钛合金基类金刚石梯度薄膜材料制备及其生物摩擦学性能和血液相容性的研究

【作者】 蒋书文；

【导师】 郑昌琼；

【作者基本信息】 四川大学 ， 生物医学工程， 2002， 博士

【摘要】 本研究采用等离子源离子注入—离子束增强沉积技术（PSII-IBED）制备了钛合金基类金刚石梯度薄膜材料，对类金刚石梯度薄膜这一新型人工关节材料和人工心脏瓣膜材料的生物摩擦学性能和血液相容性进行了研究和评价，研究了摩擦磨损对材料血液相容性的影响。 1．对制备的DLC梯度薄膜材料的有关物理性能、表面形貌、热应力等进行了测定或计算。类金刚石薄膜梯度材料由大小分布均匀，表面光滑的非晶态微小颗粒组成。表面显微硬度约为Ti6A14V合金基体的3倍。薄膜与基体之间的结合强度不低于0.8GPa。 2．研究了DLC梯度薄膜材料与UHMWPE组成的摩擦副的生物摩擦学性能，探讨了摩擦磨损机理。Ti6A14V基DLC梯度薄膜材料具有较好的减摩特性和耐磨损特性。与Ti6A14V合金相比，能够有效地降低摩擦系数，降低磨损。在干摩擦、Hank’s溶液和生理盐水润滑条件下，摩擦系数分别降低24％、5.0％和10％，体积磨损率约为相同条件下Ti6A14V合金磨损率的50％。DLC膜的减摩机理与其表面高硬度含氢非晶态碳膜结构和成分有关，磨损形式主要是轻微的磨粒磨损。与此同时DLC膜也降低了UHMWPE的磨损。 3．采用血小板消耗率测定、血浆蛋白吸附、血小板粘附变形实验方法研究了材料的血液相容性。DLC梯度薄膜材料与Ti6A14V合金材料的血小板消耗率相差不大，但是DLC梯度薄膜材料对血浆蛋白的吸附明显低于Ti6A14V合金材料，可以预料血小板在DLC梯度薄膜材料表面粘附也会较少。血小板粘附变形实验表明，血小板在DLC梯度薄膜材料表面的粘附率略低于Ti6A14V材料表面的粘附率。对粘附在材料表面的血小板的形态参数的统计分析结果也表明，DLC梯度薄膜材料表面有更少数量的血小板处于激活状态，对血小板的形态影响较小。综合以上结果，可以认为DLC梯度薄膜材料具有比Ti6A14V合金材料更为优越的血液相容性。 4．研究了摩擦磨损对材料血液相容性的影响。材料血液相容性与材料表面性能结构密切相关。DLC梯度薄膜材料在摩擦磨损实验前后薄膜结构成分和表面形貌变化较小，仍能保持较好的血液相容性。实验结果表明，摩擦磨损导致Ti6A14V合金表面TiO₂膜的破坏，表面粗糙程度大幅增加，血液相容性受摩擦磨损影响较大。 5．摩擦表面具有多尺度相似性和随机性的特点，采用分形几何理论描述表面的粗糙程度及形貌特征，三维表面的分形维数可以作为一种尺度无关的粗糙度评定参数，利用图象处理方法，通过材料表面的扫描电镜SEM图象灰度数据来计算三维表面的分形维数。 J 6．利用计算机图象处理和图象分析方法，对血液相容性评价方法进行了改 A ＼进。应用计算机图象处理和图象分析的方法对血小板进行自动计数，开发了自 厂动i！数计算机程序，提高了血小扳消耗率测定实验结果的客观性和准确性。引入形态学参数和分形维数定量描述血小扳变形程度，建立了血小板形态参数分布与生物材料血液相容性之间的关系。更多还原

【Abstract】 Diamond-like carbon gradient film on Ti6A14V alloy substrate have been prepared by means of plasma source ion implanted-ion beam enhanced deposition(PSII-IBED). For potential applications as artificial joint materials and artificial cardiac valve materials,its trobological performance and hemocompatibility has also been evaluated in the present Ph.D. thesis.The surface structure,morphology and internal thermal stress of DLC gradient film materials had been characterized or calculated. It was showed that the DLC gradient film has a smooth surface with noncrystal amorphous structure,its surface vicker’s hardness was as about three times as that of Ti6A14V alloy substrate,and high adhension strength of no less than O.SGPa between DLC film and substrate was estimated by liquid quench method.The friction and wear behavior of DLC gradient film on TJ6A14V alloy substrate sliding against ultra-high molecular weight polyethylene was investigated by comparing with that of Ti6A14V alloy against the same counterpart under the same testing conditions. It has been found that the diamond-carbon-like gradient film has good friction-reduction and wear-resistant behavior in sliding against the polymer counterpart. The coefficients of friction reduced 24%,5.0%,10% than these of Ti6A14V under dry sliding and lubrication of Hank’s solution and 0.9% NaCl solution respectively,and its wear rate were about half of that of T16A14V under the same condition. Especially,it also registered a lower wear rate of the polymer counterpart compared with Ti6A14V alloy. The worn surfaces of the tested samples were observed with a scanning electron microscope,as an effort to analyze the wear mechanisms. The wear of the diamond-carbon-like gradient film is characterized by slight abrasive wear which is able to be refrained by the polymer counterpart. Friction-reduction mechanism of DLC gradient film could be attributed to its smooth and hard amorphous structure.The hemocompatibility of DLC gradient film had been evaluated by investigating platelet consumption ratio,blood protein adsorption and plateletadhension and morphology on surface of materials. It showed that DLC gradient film had a better hemocompatibllity than T16A14V alloy since that DLC gradient film had lower adsorption ratio to blood protein and less effect on platelet adhension and morphology,though its platelet consumption ratio was almost as same as that of T16A14V alloy.The effect of friction and wear on hemocompatibility of materials was also investigated,since the hemocompatibility of bio-medical material is closely related to its surface structure and roughness. For comparison,that of the Ti6Al4V alloy sliding against UHMWPE was also evaluated. It was showed that DLC gradient film material had a good stability of hemocompatibility,for its surface almost had no changes. In comparison,the hemocompatibility of T16A14V became worse since its surface had been heavily scratched and dense oxide films on its surface had been destroyed.Fratal theory and image processing method had been applied to calculate the fratal dimension of tribological surfaces furthermore to elavuate the surface morphology and roughness. Evaluation on hemocompatibility of bio-materials had also been improved by image processing and analysis method,the relationship between mathematical morphological parameters of platelets adhered to bio-material surface and hemocompatibility of bio-materials had been established.更多还原