Study on the Mg-Li-Zn ternary alloy system with improved mechanical properties, good degradation performance and different responses to cells

Publication date: Available online 17 August 2017
Source:Acta Biomaterialia
Author(s): Yang Liu, Yuanhao Wu, Dong Bian, Shuang Gao, Sander Leeflang, Hui Guo, Yufeng Zheng, Jie Zhou
Novel Mg-(3.5, 6.5 wt.%)Li-(0.5, 2, 4 wt.%)Zn ternary alloys were developed as a new kind of biodegradable metallic materials with potential for stent applications. Their mechanical properties, degradation behavior, cytocompatibility and hemocompatibility were studied. These potential biomaterials showed higher ultimate tensile strength than those of 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)2, MgCO3 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.

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