微量元素改性钛合金抗菌性生物活性涂层的制备及性能研究

Trace elements in bone such as magnesium, zinc and copper possess bioactivity. In addition, zice and copper have antibacterial property. However, their contents must be strictly controlled, and the excess amounts can cause deleterious effects. In order to give overal consideration to the coating biocompatibility, bioactivity and antibacterial property, the principles of bionics are used in the project. Based on the composition of natural bone, magnesium, zinc and copper salts are added into the base solution containing calcium and phosphorus electrolytes. Antibacterial bioactive coating will be fabricated by one-step micro arc oxidation (MAO) on titanium alloy surface. The influences of magnesium, zinc and copper salts concentrations and electric parameters on coating compositions and microstructure will be studied, and the mechanism of cations taking part in the coating formation will be clarified. The influences of single, dual and ternary element contents and the microstructure of anodic coatings on in vitro biocompatibility, bioactivity and antibacterial property are separately investigated, and the regularity of trace elements influencing the biological performance of anodic coatings with each other is also clarified. The coating structure with excellent biological performance and its preparation technology will be obtained by using the Taguchi experiment. In vivo biocompatibility and the mechanism of inducing new bone formation by trace elements are discussed by the animal implantion test. The research achievements will clarify the influencing regularity of trace elements on the biological performance of anodic coatings in vitro and in vivo, establish the model of new bone development in vivo on the surface of the MAO treated titanium alloys. These results will provide the important theoretical foundation and experimental data for the development of antibacterial bioactive coating on medical titanium alloys.

骨头中的镁、锌和铜等微量元素不仅对骨生长起到重要作用，而且锌和铜还具有抗菌性，但它们的用量须严格控制，过量则引起副作用。为兼顾涂层生物相容性、生物活性和抗菌性，本项目应用仿生学原理，从天然骨的成分出发，在含钙磷盐溶液中，添加镁、锌和铜盐，采用一步微弧氧化在钛合金表面制备抗菌性生物活性涂层。拟开展镁、锌和铜盐浓度和电参数对涂层组成和微观结构的影响，揭示阳离子进入氧化膜的机制。分别研究涂层中一元、二元和三元元素含量和微观结构对涂层体外生物相容性、生物活性和抗菌性影响，清晰元素之间相互影响涂层生物学性能的规律。使用正交实验，获得具有良好生物学性能的涂层结构与制备工艺。采用动物体内植入实验，探讨元素体内生物相容性和诱导新骨形成机制。研究成果有望清晰微量元素对涂层体外、体内生物学性能影响的规律，建立处理后的钛合金体内新骨形成模型，为在钛合金表面开发抗菌性生物活性涂层提供重要的理论基础和实验依据。

由于密度小、比强度高、优异的耐蚀性和生物相容性，钛合金广泛用于外科植入材料。但是，钛合金属于生物惰性材料，且不具有抗菌性。微弧氧化是一种有效的表面处理处理方法，能显著提高钛合金性能。镁、锌和铜等微量元素不仅对骨生长起到重要作用，而且锌和铜还具有抗菌性。为兼顾涂层生物相容性、生物活性和抗菌性，在仅含15 g/L环保型有机含磷电解质植酸溶液中，制备的微弧氧化样品具有很好的体外生物相容性。.采用四因素三水平正交实验研究了植酸、EDTA-ZnNa2、KOH浓度和处理时间对微弧氧化膜中锌和磷含量的影响。植酸是影响氧化膜中锌和磷含量的最重要因素，氧化膜中的锌和磷以Zn3(PO4)2存在。随着植酸浓度增加或KOH浓度减少，氧化膜中锌和磷含量表现出增加的趋势。磷以扩散进入氧化膜中，而锌和来自植酸中的磷进入氧化膜中。.研究了EDTA-CaNa2浓度、EDTA-MgNa2浓度、氢氧化钾浓度和终电压对氧化膜中镁和钙含量的影响。钙和镁分别通过扩散进入氧化膜中；两种元素之间的竞争作用不明显。增加氢氧化钾浓度能同时增加氧化膜中钙含量和镁含量。在相同工艺参数条件下，氧化膜中钙含量比镁含量更高。.使用含EDTA-CuNa2、KOH和植酸的电解液，在钛合金表面制备含铜微弧氧化膜。另外，首次检测了阴极表面特征。结果表明，使用的电解质通过影响溶液pH值和电导率决定氧化膜成分和表面形貌。微弧氧化过程中，铜同时在阳极参与氧化膜的形成和在阴极析出。.含铜1.92 wt%的氧化样品在Hank溶液中浸泡14天后，对金黄色葡萄糖球菌的抗菌率仍为100%；而浸泡8天和14天后对大肠杆菌的抗菌率分别为92%和12%，说明Cu-1.92 wt%具有良好的抗菌持续性。另外，Cu-1.92 wt%样品有助于初期的细胞粘附和增殖。以上结果表明制备的含铜氧化膜拥有良好的生物相容性和体外长期抗菌性能，具有很好的应用前景。