【作者】 李龙川；

【导师】 高家诚；

【作者基本信息】 重庆大学 ， 材料学， 2004， 硕士

【摘要】 生物材料不仅在提高人类的生活质量、保护人类健康、挽救生命等方面具有重大的社会效益，而且已经成为各国经济新的增长点。虽然现今已有很多种类的金属基生物材料广泛应用于临床，但在这些生物材料当中，没有一种的性能能够完全满足人们的需要。因此，开发新型的金属基生物材料是有必要而且是十分迫切的。 镁及镁合金由于密度低，比强度、比刚度高等优异的综合性能已被较为广泛地应用在航空航天、电子通信等领域。但将纯镁及镁合金应用在生物材料领域，还未见报道。本文研究了用碱热处理、热—有机膜表面改性两种仿生矿化法对纯镁进行表面处理的工艺，使得改性后的纯镁能在仿生体液（SBF）中迅速获得具有生物活性的表面。研究中采用了扫描电镜、X射线衍射仪、能谱仪、傅立叶红外光谱、热分析等分析手段对试样表面进行了显微组织观察、物相结构、成分分析等方面的研究。此外，本文首次对纯镁的细胞毒性与血液相容性进行了测试和分析。 实验结果表明：碱热处理法中，在初始pH=9.3的过饱和NaHCO₃—MgCO₃混合溶液中，纯镁表面能迅速沉积一层轻质碳酸镁晶体层。再经过热处理后，该晶体层呈半熔化，冷却后呈现不规则块状，变得更为致密。热处理还能在纯镁基体上产生一层厚约20μm的氧化镁层。碱热处理后的纯镁试样在SBF溶液浸泡180d没有任何的质量损失。并且在表面生成了钙磷基的沉淀；在热—有机膜表面改性的实验中，处理过的纯镁试样在SBF溶液中表现了良好的耐腐蚀性能，并且表面迅速（＜24h）沉积了羟基磷灰石（HA）和磷酸八钙（OCP）的混合钙磷基沉淀。生物相容性实验结果表明：纯镁对小鼠骨髓细胞无细胞毒性；未处理的纯镁有溶血现象，但热处理、热—有机膜处理的纯镁没有溶血现象发生。 最后，本文还着重讨论了在沉积过程中，钙磷基沉淀在试样表面析出的热力学条件和溶液中离子与试样表面相互作用的机理，探讨了纯镁在生物材料领域应用的可能性。更多还原

【Abstract】 Biomaterials not only have important social effect in bettering the living quality of human beings, improving their health and saving their lives, but also become a new growth point in economic and scientific-technological areas. At present, though a variety of metallic biomaterials have been developed and widely used in clinic, none of them is ideal. Therefore, it is necessary and urgent to develop new metallic biomaterials.In this study, the alkali-heat treatment and heat-organic layers treatment techniques were studied to make the treated samples obtain bioactive surface when soaked in SBF. SEM, XRD, EDX and FTIR analysis were employed to examine the samples at various intervals. Biocompatibility tests, including cytocompatibility and hemolysis tests, were also conducted to testify the possibility of using magnesium in biomedical fields. The results showed that in alkali-heat treatment, the samples obtained a coating of light magnesium carbonate quickly after they were soaked in supersaturated NaHCO3-MgCO3 solution with the starting pH of 9.3. The coating became half-melted and denser when they were heat-treated. More important, an oxide layer with the thickness of 20nm was formed after heat treatment. The high corrosion resistance of treated sampled could be demonstrated by the fact that no specific mass loss was observed when they were soaked in SBF for 180d. Calcium-phosphate based apatites were also detected on the surface of samples subjected to 180d-soaking experiment in SBF.In the heat and organic layer-treatment, the treated samples showed good corrosion resistance and obtained HA and OCP precipitates in SBF within 24h. The biocompatibility test results showed that magnesium had no inhibitory effect on the proliferation of marrow cells; whereas heat-treated and heat-organic films-treated samples caused no hemolysis, untreated magnesium had obvious hemolytic effect.In the end, thermodynamic conditions for precipitating HA, interactions between the ions in the solution and substrate and possibility of employing magnesium in biomedical fields were discussed .更多还原