School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China.
J Biomed Mater Res A. 2012 Apr;100(4):999-1015. doi: 10.1002/jbm.a.34042. Epub 2012 Feb 5.
A novel biodegradable Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy was successfully produced using a series of metallurgical processes; including melting, casting, rolling, and heat treatment. The hardness and ultimate tensile strength of the alloy sheets increased to 71.2HV and 320 MPa after rolling and then aging for 12 h at 175°C. These mechanical properties were sufficient for load-bearing orthopedic implants. A hydroxyapatite (HA) coating was deposited on the Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy using a novel coating process combining alkali heat pretreatment, electrodeposition, and alkali heat posttreatment. The microstructure, composition, and phases of the Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy and HA coating were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The degradation, hemolysis, and cytocompatibility of the HA-coated and uncoated Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy were studied in vitro. The corrosion potential (E(corr)) of Mg-4.0Zn-1.0Ca-0.6Zr alloy (-1.72 V) was higher than Mg (-1.95 V), Mg-0.6Ca alloy (-1.91 V) and Mg-1.0Ca alloy (-1.97 V), indicating the Mg-Zn-Ca-Zr alloy would be more corrosion resistant. The initial corrosion potential of the HA-coated Mg alloy sample (-1.51 V) was higher than the uncoated sample (-1.72 V). The hemolysis rates of the HA-coated and uncoated Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy samples were both <5%, which met the requirements for implant materials. The HA-coated and uncoated Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy samples demonstrated the same cytotoxicity score as the negative control. The HA-coated samples showed a slightly greater relative growth rate (RGR%) of fibroblasts than the uncoated samples. Both the HA-coated and uncoated Mg-4.0Zn-1.0Ca-0.6Zr (wt %) alloy provided evidence of acceptable cytocompatibility for medical applications.
一种新型可生物降解的 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金通过一系列冶金工艺成功制备；包括熔炼、铸造、轧制和热处理。经过轧制和 175°C 时效 12 小时后，合金板材的硬度和极限拉伸强度提高到 71.2HV 和 320MPa。这些机械性能足以满足承重骨科植入物的要求。使用一种将碱热预处理、电沉积和碱热后处理相结合的新型涂层工艺，在 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金上沉积了羟基磷灰石（HA）涂层。使用扫描电子显微镜（SEM）、能量色散 X 射线光谱（EDS）和 X 射线衍射（XRD）对 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金和 HA 涂层的微观结构、组成和相进行了表征。体外研究了 HA 涂层和未涂层 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金的降解、溶血和细胞相容性。Mg-4.0Zn-1.0Ca-0.6Zr 合金的腐蚀电位（E（corr））（-1.72V）高于 Mg（-1.95V）、Mg-0.6Ca 合金（-1.91V）和 Mg-1.0Ca 合金（-1.97V），表明 Mg-Zn-Ca-Zr 合金的耐腐蚀性更强。HA 涂层镁合金样品的初始腐蚀电位（-1.51V）高于未涂层样品（-1.72V）。HA 涂层和未涂层 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金样品的溶血率均<5%，符合植入材料的要求。HA 涂层和未涂层 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金样品的细胞毒性评分与阴性对照相同。HA 涂层样品的成纤维细胞相对生长率（RGR%）略高于未涂层样品。HA 涂层和未涂层 Mg-4.0Zn-1.0Ca-0.6Zr（wt%）合金均为可接受的细胞相容性，适用于医疗应用。
