表面钝化对316L医用不锈钢血液相容性的影响

IMR OpenIR

	表面钝化对316L医用不锈钢血液相容性的影响
	史永娟
学位类型	硕士
导师	杨柯 ; 任伊宾
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料加工工程
关键词	316l不锈钢表面钝化电化学腐蚀血液相容性蛋白吸附表面性能 316l Stainless Steel Surface Passivation Electrochemical Corrosion Blood Compatibility Protein Adsorption Surface Property
摘要	"316L不锈钢由于具有良好的力学性能和耐蚀性能，令人满意的生物相容性以及价格低廉等综合优势而被广泛用于医疗领域。然而，当与体液相接触时，在含有氯离子和生物分子的环境中不可避免会发生腐蚀，溶出一些金属离子，可能会引起发炎等副作用，因此医用316L不锈钢的耐蚀性能和表面特性始终是影响其临床应用的重要问题。表面钝化既能提高不锈钢的耐蚀性能，还可以改善不锈钢的表面性能，是医用不锈钢常用而且有效的表面处理方法。本文重点研究了医用不锈钢的钝化新方法—316L不锈钢耐蚀性能、表面性能和血液相容性的影响，以及它们相互之间的关系，得到如下主要研究结果：柠檬酸钝化对电化学测试的结果表明，经过柠檬酸钝化的316L不锈钢的耐蚀性能得到很大提高。在开路电位下，相对于硝酸钝化和未钝化样品，其自腐蚀电位较高，自腐蚀电流较小，极化电阻较大，但其点蚀电位较硝酸钝化样品稍低。在含有白蛋白和纤维蛋白原的电解液中的生物腐蚀行为研究表明，纤维蛋白原对不锈钢钝化前后表面均起保护作用，但白蛋白恶化未钝化不锈钢的耐蚀性能，而对硝酸钝化和柠檬酸钝化后不锈钢表面起到保护作用。经过柠檬酸钝化之后，316L不锈钢表面的亲水性增加，这主要与其钝化后表面能增大有关。XPS分析结果表明，经过柠檬酸和硝酸钝化之后，各元素在不锈钢表面的分布发生了改变，同时表面成分的变化引起了不锈钢表面钝化膜的半导体性质发生变化。316L不锈钢钝化前表面主要呈现n型半导体性质，而经过硝酸钝化和柠檬酸钝化的不锈钢表面在低电位区间呈p型半导体性质，在高电位区间呈现n型半导体性质。钝化前后的316L不锈钢均无溶血现象，凝血时间测量和血小板黏附等实验的结果表明柠檬酸钝化后的316L不锈钢具有较好的血液相容性。柠檬酸钝化后316L不锈钢血液相容性的改善与其钝化后表面能增大和表面吸附白蛋白比例增加有密切关系，白蛋白可以有效阻碍血小板在材料表面的黏附和聚集。同时柠檬酸钝化后表面吸附的柠檬酸分子与血液成分的相互作用减缓了凝血过程。另外柠檬酸钝化后316L不锈钢血液相容性改善也与其表面耐蚀性提高以及表面金属阳离子溶出减少有一定关系。综上所述，柠檬酸钝化可以有效地提高316L不锈钢表面耐蚀性能，增加表面的亲水性，提高不锈钢的血液相容性，因此柠檬酸钝化可作为心血管领域不锈钢植入器件的有效的表面钝化方法，以提高不锈钢植入器件生物相容性."
其他摘要	"316L stainless steel is widely used in the field of clinical treatments because of its good mechanical properties and corrosion resistance, satisfactory biocompatibility and relatively lower cost. However, when contacting with the body fluid, which contains chloride ions and biomolecules, the corrosion of this steel will inevitably occur, releasing some metallic ions which may lead to side effects such as inflammation. So the corrosion resistance and surface characteristics are the two most important factors that influence the clinical application of the 316L stainless steel. Passivation can change not only the corrosion resistant behavior, but also the surface properties of 316L. In this study, the influence of a new passivation method, citric acid passivation, on the corrosion resistance, surface characteristics and blood compatibility of 316L stainless steel, as well as the relationship between each other, were mainly studied. The results are summarized as following: Electrochemical tests results showed that the corrosion resistance of 316L stainless steel after passivation by citric acid was largely improved. At the open circuit potential, its corrosion resistance was higher, corrosion current was smaller and the charge transfer resistance was larger than the untreated and nitric acid passivated steels. But its breakdown potential was a little bit lower than that of the passivation by nitric acid. Study on bio-corrosion behavior of 316L stainless steel in the albumin or fibrinogen containing simulated body fluids showed that fibrinogen played a protective effect on the surface of 316L stainless steel both before or after passivation. However, on the surface of the untreated 316L stainless steel, the albumin deteriorated the corrosion resistance of the steel. While on the surface of the steel passivated by nitric acid or citric acid, the albumin could protect the steel from the corrosion. After passivation by citric acid, the wettability of the 316L stainless steel became much better which was attributed to the increase of surface energy. XPS results showed that the states of all the elements on the surface of 316L stainless steel passivated by both nitric acid and citric acid were changed a lot and the change of surface composition led to the change of the feature of semiconductor of the passivation layer. The untreated 316L steel exhibited as an n-type semiconductor while after either nitric acid or citric acid passivation the steel exhibited a p-type semiconductor in the lower potential region and n-type in the higher potential region. No hemolysis was found for 316L stainless steel before and after passivation , and coagulation time measurement and platelet adhesion test showed that the samples passivated by citric acid behaved better blood compatibility. It was contributed to the increase of surface energy and the higher ration of albumin adsorption. The albumin could effectively block the adhesion and aggregation of the platelet. At the same time, the interaction of the citric acid adsorbed on the surface and the blood slowed down the blood coagulation process. In addition, the improvement of the blood compatibility of 316L stainless steel after passivation by citric acid was also in a certain extent due to its better corrosion resistance and thus relatively lower metallic ions release. In summary, the citric acid passivation could effectively improve the corrosion resistance ,increased the surface wettability and the haemocompatibility. As a result, it can be applied in the field of coronary artery stent implantation as a new effective surface passivation methods in order to enhance the biocompatibility. "
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64526
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	史永娟. 表面钝化对316L医用不锈钢血液相容性的影响[D]. 北京. 中国科学院金属研究所,2012.