Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
Acta Biomater. 2017 Oct 15;62:418-433. doi: 10.1016/j.actbio.2017.08.021. Epub 2017 Aug 17.
Novel Mg-(3.5, 6.5wt%)Li-(0.5, 2, 4wt%)Zn ternary alloys were developed as new kinds of biodegradable metallic materials with potential for stent application. Their mechanical properties, degradation behavior, cytocompatibility and hemocompatibility were studied. These potential biomaterials showed higher ultimate tensile strength than previously reported binary Mg-Li alloys and ternary Mg-Li-X (X=Al, Y, Ce, Sc, Mn and Ag) alloys. Among the alloys studied, the Mg-3.5Li-2Zn and Mg-6.5Li-2Zn alloys exhibited comparable corrosion resistance in Hank's solution to pure magnesium and better corrosion resistance in a cell culture medium than pure magnesium. Corrosion products observed on the corroded surface were composed of Mg(OH), MgCO and Ca-free Mg/P inorganics and Ca/P inorganics. In vitro cytotoxicity assay revealed different behaviors of Human Umbilical Vein Endothelial Cells (HUVECs) and Human Aorta Vascular Smooth Muscle Cells (VSMCs) to material extracts. HUVECs showed increasing nitric oxide (NO) release and tolerable toxicity, whereas VSMCs exhibited limited decreasing viability with time. Platelet adhesion, hemolysis and coagulation tests of these Mg-Li-Zn alloys showed different degrees of activation behavior, in which the hemolysis of the Mg-3.5Li-2Zn alloy was lower than 5%. These results indicated the potential of the Mg-Li-Zn alloys as good candidate materials for cardiovascular stent applications.
Mg-Li alloys are promising as absorbable metallic biomaterials, which however have not received significant attention since the low strength, controversial corrosion performance and the doubts in Li toxicity. The Mg-Li-Zn alloy in the present study revealed much improved mechanical properties higher than most reported binary Mg-Li and ternary Mg-Li-X alloys, with superior corrosion resistance in cell culture media. Surprisingly, the addition of Li and Zn showed increased nitric oxide release. The present study indicates good potential of Mg-Li-Zn alloy as absorbable cardiovascular stent material.
新型 Mg-(3.5、6.5wt%)Li-(0.5、2、4wt%)Zn 三元合金被开发为具有支架应用潜力的新型可生物降解金属材料。研究了它们的力学性能、降解行为、细胞相容性和血液相容性。这些潜在的生物材料的极限拉伸强度高于以前报道的二元 Mg-Li 合金和三元 Mg-Li-X（X=Al、Y、Ce、Sc、Mn 和 Ag）合金。在所研究的合金中，Mg-3.5Li-2Zn 和 Mg-6.5Li-2Zn 合金在 Hank's 溶液中的耐腐蚀性与纯镁相当，在细胞培养基中的耐腐蚀性优于纯镁。在腐蚀表面观察到的腐蚀产物由 Mg(OH)、MgCO 和无钙的 Mg/P 无机物和无钙的 Ca/P 无机物组成。体外细胞毒性试验显示人脐静脉内皮细胞（HUVEC）和人主动脉血管平滑肌细胞（VSMC）对材料提取物的不同行为。HUVEC 表现出一氧化氮（NO）释放增加和可耐受的毒性，而 VSMC 则表现出随时间推移活力逐渐降低的有限毒性。这些 Mg-Li-Zn 合金的血小板黏附、溶血和凝血试验显示出不同程度的激活行为，其中 Mg-3.5Li-2Zn 合金的溶血率低于 5%。这些结果表明，Mg-Li-Zn 合金作为心血管支架应用的候选材料具有潜力。
Mg-Li 合金作为有前途的可吸收金属生物材料，由于强度低、腐蚀性有争议以及对 Li 毒性的怀疑，尚未得到广泛关注。本研究中的 Mg-Li-Zn 合金的机械性能得到了显著提高，高于大多数报道的二元 Mg-Li 和三元 Mg-Li-X 合金，在细胞培养基中的耐腐蚀性更好。令人惊讶的是，Li 和 Zn 的添加增加了一氧化氮的释放。本研究表明，Mg-Li-Zn 合金作为可吸收心血管支架材料具有良好的应用潜力。
