生物活性涂层包覆镁合金的制备与性能研究

发布时间：2018-03-02 04:39

本文关键词： 镁合金生物活性涂层微波耐蚀性能细胞相容性　出处：《天津大学》2016年博士论文　论文类型：学位论文

【摘要】：镁及镁合金具有良好的生物相容性和力学相容性,是很有潜力的一类可降解植入材料。然而,镁及镁合金在组织体液中降解过快,限制了其临床应用。生物活性涂层表面改性是提高镁及镁合金耐蚀性能的有效方法。理想的生物活性涂层需具备一定的致密度、厚度与矿化能力,同时,还应具备一定的粘附强度,减缓保护涂层的剥落。因此,在镁及镁合金表面制备具有上述性能的生物活性涂层,有望获得具有良好综合性能的骨修复材料。采用溶胶凝胶-浸渍提拉法结合热处理以及轴向加压,在镁合金(AZ31)表面制备了45S5涂层。热处理和轴向加压可以调节涂层的致密度和界面残余应力。经400°C热处理和4 MPa轴向加压得到的涂层具有较高的致密度,涂层与镁合金界面没有明显缺陷,涂层的粘附强度为25.8±2.6 MPa。随着在SBF(模拟体液)中浸泡时间的延长,涂层表面形成了颗粒堆积结构的矿化层,浸泡17天之后,镁合金的失重为8.9±0.7 mg/cm2。采用微波液相化学法仅需10 min在镁合金表面制备了硅掺杂羟基磷灰石双层涂层:表层为絮状HA(羟基磷灰石),底层为长片状HA,涂层的厚度为?10.7μm。涂层的粘附强度为6.7±0.7 MPa。SBF浸泡实验结果表明:长片状HA为镁合金提供了初期保护作用;絮状HA具有优异的矿化能力,形成的矿化层为镁合金提供了长期保护作用,浸泡24天之后,镁合金的失重为5.4±0.4 mg/cm2。涂层具有较高的细胞活性,上调了I型胶原蛋白和骨钙蛋白的表达。采用微波液相化学法仅需10 min在镁合金表面制备了氟掺杂羟基磷灰石双层涂层:表层为直径35 nm至45 nm的晶须状HA,底层主要为直径70 nm至80 nm的晶须状HA。涂层具有较低的溶解性和优异的矿化能力,形成的矿化层为镁合金提供了长期保护作用,浸泡24天之后,镁合金的失重为4.0±0.3 mg/cm2。晶须状HA构成的分级纳米-微米结构提高了涂层的表面生物活性,显著上调了MC3T3-E1成骨细胞主要分化标记物的表达,增强了成骨细胞的分化。氟掺杂羟基磷灰石涂层对镁合金提供长期保护作用,并改善了细胞相容性,有望作为可降解镁及镁合金的保护涂层而使用。
[Abstract]:Magnesium and magnesium alloys have good biocompatibility and mechanical compatibility and are potential biodegradable implants. The surface modification of bioactive coating is an effective method to improve the corrosion resistance of magnesium and magnesium alloys. The ideal bioactive coating should have a certain density, thickness and mineralization ability, at the same time, There should also be a certain adhesion strength to slow down the spalling of protective coatings. Therefore, bioactive coatings with the above properties should be prepared on magnesium and magnesium alloys. It is expected that the bone repair materials with good comprehensive properties can be obtained. The sol-gel dipping and drawing method combined with heat treatment and axial compression are used. 45S5 coating was prepared on the surface of magnesium alloy AZ31. The density and interface residual stress of the coating can be adjusted by heat treatment and axial compression. The coating obtained by heat treatment at 400 掳C and axial pressure by 4 MPa has high density. There was no obvious defect in the interface between the coating and magnesium alloy, and the adhesion strength of the coating was 25.8 卤2.6 MPA. With the prolongation of soaking time in SBF (simulated body fluid), a mineralized layer with granular stacking structure was formed on the surface of the coating, which was soaked for 17 days. The weight loss of magnesium alloy was 8.9 卤0.7 mg / cm ~ 2. Si-doped hydroxyapatite double layer coating was prepared on magnesium alloy surface by microwave liquid chemical method for only 10 min. The adhesion strength of the coating was 6.7 卤0.7 MPa.SBF. The results showed that the long sheet HA provided initial protection for magnesium alloy, the flocculent HA had excellent mineralization ability, and the mineralized layer provided long-term protection for magnesium alloy. After immersion for 24 days, the weight loss of magnesium alloy was 5.4 卤0.4 mg / cm ~ 2. The expression of type I collagen and osteocalcin was upregulated. Fluorine-doped hydroxyapatite bilayer coating was prepared on magnesium alloy surface by microwave liquid phase chemical method for only 10 min. The surface layer was whisker HA with diameter from 35 nm to 45 nm. The coating has low solubility and excellent mineralizing ability. The mineralized layer provided long-term protection for magnesium alloy. After immersion for 24 days, the weight loss of magnesium alloy was 4.0 卤0.3 mg / cm ~ 2.The graded nano-micron structure of whisker HA enhanced the surface bioactivity of the coating. The expression of major differentiation markers of MC3T3-E1 osteoblasts was up-regulated, and the differentiation of osteoblasts was enhanced. Fluorine-doped hydroxyapatite coating provided long-term protection to magnesium alloys and improved the cytocompatibility of magnesium alloys. It is expected to be used as a protective coating for degradable magnesium and magnesium alloys.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG178

【相似文献】