The development of binary Mg-Ca alloys for use as biodegradable materials within bone
The development of binary Mg-Ca alloys for use as biodegradable materials within bone
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开发用作骨内可生物降解材料的二元镁钙合金
DOI：
10.1016/j.biomaterials.2007.12.021
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发表时间：
2008-04-01
期刊：
影响因子：
14
通讯作者：
Zheng, Yufeng
中科院分区：
文献类型：
--
作者：
Li, Zijian;Gu, Xunan;Zheng, Yufeng
在不同的工作条件下制备了不同钙含量的Mg-Ca二元合金。x射线衍射（XRD）分析和光学显微镜观察表明，Mg- xca （x = 1-3 wt%）合金由α (Mg)和Mg2Ca两相组成。拉伸试验和体外腐蚀试验结果表明，通过控制Ca含量和工艺处理可以调节合金的力学性能。随着钙含量的增加，屈服强度（YS）、极限抗拉强度（UTS）和伸长率降低。铸态Mg-1Ca合金经热轧（166.7 +/- 3.01 MPa和3 +/- 0.78%）和热挤压（239.63 +/- 7.21 MPa和10.63 +/- 0.64%）后的UTS和伸长率（71.38 +/- 3.01 MPa和1.87 +/- 0.14%）均有较大提高。模拟体液体外腐蚀试验表明，Mg-xCa合金的显微组织和工作历史对其腐蚀行为有较大影响。随着Mg2Ca相含量的增加，腐蚀速率提高，而热轧和热挤压可以降低腐蚀速率。对L-929细胞进行细胞毒性评价，结果表明Mg-1Ca合金对细胞不产生毒性，细胞在Mg-1Ca合金萃取液中的活力优于对照。将Mg-1Ca合金钉分别植入兔左、右股轴，以市售纯钛钉为对照，观察1、2、3个月。苏木精和伊红染色的组织切片显示，Mg-1Ca合金针周围有高活性的成骨细胞和骨细胞。x线检查显示Mg-1Ca合金钉在体内90天内逐渐降解，3个月时清晰地看到新形成的骨。体外和体内腐蚀均表明，随着浸渍时间的延长，Mg- 1ca合金表面形成了Mg(OH)(2)和羟基磷灰石的混合物。不同降解阶段血清镁含量无显著差异（p < 0.05）。结果表明，Mg-1Ca合金具有良好的生物相容性，是一种新型的可降解种植体材料。在此基础上，提出了固体合金/液体溶液界面模型来解释生物腐蚀过程和相关的羟基磷灰石矿化。(c) 2007 Elsevier Ltd.版权所有。
Binary Mg-Ca alloys with various Ca contents were fabricated under different working conditions. X-ray diffraction (XRD) analysis and optical microscopy observations showed that Mg-xCa (x = 1-3 wt%) alloys were composed of two phases, alpha(Mg) and Mg2Ca. The results of tensile tests and in vitro corrosion tests indicated that the mechanical properties could be adjusted by controlling the Ca content and processing treatment. The yield strength (YS), ultimate tensile strength (UTS) and elongation decreased with increasing Ca content. The UTS and elongation of as-cast Mg-1Ca alloy (71.38 +/- 3.01 MPa and 1.87 +/- 0.14%) were largely improved after hot rolling (166.7 +/- 3.01 MPa and 3 +/- 0.78%) and hot extrusion (239.63 +/- 7.21 MPa and 10.63 +/- 0.64%). The in vitro corrosion test in simulated body fluid (SBF) indicated that the microstructure and working history of Mg-xCa alloys strongly affected their corrosion behaviors. An increasing content of Mg2Ca phase led to a higher corrosion rate whereas hot rolling and hot extrusion could reduce it. The cytotoxicity evaluation using L-929 cells revealed that Mg-1Ca alloy did not induce toxicity to cells, and the viability of cells for Mg-1Ca alloy extraction medium was better than that of control. Moreover, Mg-1Ca alloy pins, with commercial pure Ti pins as control, were implanted into the left and right rabbit femoral shafts, respectively, and observed for 1, 2 and 3 months. High activity of ostroblast and osteocytes were observed around the Mg-1Ca alloy pins as shown by hematoxylin and eosin stained tissue sections. Radiographic examination revealed that the Mg-1Ca alloy pins gradually degraded in vivo within 90 days and the newly formed bone was clearly seen at month 3. Both the in vitro and in vivo corrosion suggested that a mixture of Mg(OH)(2) and hydroxyapatite formed on the surface of Mg-1Ca alloy with the extension of immersion/implantation time. In addition, no significant difference (p > 0.05) of serum magnesium was detected at different degradation stages. All these results revealed that Mg-1Ca alloy had the acceptable biocompatibility as a new kind of biodegradable implant material. Based on the above results, a solid alloy/liquid solution interface model was also proposed to interpret the biocorrosion process and the associated hydroxyapatite mineralization. (c) 2007 Elsevier Ltd. All rights reserved.