Research on Mg-Zn-Ca Alloy as Degradable Biomaterial
Research on Mg-Zn-Ca Alloy as Degradable Biomaterial
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DOI：
10.5772/23929
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
B. Zhang;Yicheng Wang;L. Geng
中科院分区：
文献类型：
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作者：
B. Zhang;Yicheng Wang;L. Geng
镁及镁合金是轻金属，具有密度低、比强度高、比刚度强等特点。镁的断裂韧性大于羟基磷灰石等陶瓷生物材料。镁的杨氏弹性模量和压缩屈服强度与皮质骨相近。尤其是镁离子在人体内大量存在，参与多种代谢反应和生物机制。人体通常每70公斤体重含有约35克镁，人体每天对镁的需求量约为350毫克。镁合金具有良好的生物力学性能和生物相容性，近年来被广泛应用于骨科和创伤外科的植入物[1~3]。各种镁合金作为生物可降解材料被广泛研究，其中一些材料表现出良好的生物相容性。例如，AZ31、AZ91、WE43、LAE442、镁钙和镁锌已被用于骨植入[4~8]。已有研究表明，镁可增强成骨反应，增加新骨形成。然而，一些镁合金中含有铝或重金属元素，对人体有潜在的毒性作用。因此，在这种独特的金属材料广泛应用于生物医学领域之前，必须解决强度不足、腐蚀速度快和有毒离子等问题。众所周知，纯镁的力学性能较差，通过合理选择合金化元素可以有效地提高镁的力学性能[1]。但是，基于上述考虑，用于可降解镁合金的合金元素的范围是相当有限的，锌、锰、钙以及可能是极少量的低毒稀土在人体内是可以耐受的，也可以延缓生物降解。因此，由于钙是人体骨骼中的重要元素，因此镁钙二元合金引起了研究者的关注。通过控制钙含量和加工处理，可以调节镁钙二元合金的力学性能和生物相容性。然而，镁钙二元合金的力学性能不足以及耐腐蚀性较低是这些合金的最大缺点[7][8]。幸运的是，近年来，由于锌是人体内丰富的营养元素之一，镁锌系统受到了越来越多的关注。此外，这是一个很大的潜力
Magnesium and magnesium alloys are light metals, which characterized a low density, high specific strength and strong specific stiffness. The fracture toughness of magnesium is greater than that of ceramic biomaterials such as hydroxyapatite. The Young’s elastic modulus and compressive yield strength of magnesium are closer to those of cortical bone. Especially, Mg2+ is present in large amount in the human body and involved in many metabolic reactions and biological mechanisms. The human body usually contains approximately 35g per 70kg body weight and the human body’s daily demand for Mg is about 350 mg/day. Due to the excellent biomechanical properties and biocompatibility, magnesium alloys used to be introduced as implants into orthopedic and trauma surgery in recently years [1~3].Various magnesium alloys have been investigated as biodegradable materials and some of them have been shown good biocompatibility. For example, AZ31, AZ91, WE43, LAE442, Mg-Ca and Mg-Zn have been investigated for bone implant application [4~8]. It has been shown that magnesium enhances osteogenesis response and increases newly formed bone. However, some magnesium alloys containing aluminum or heavy metal elements which have latent toxic effects on the human body. Thus, several problems such as inadequate strength, rapid corrosion and toxic ions must be solved before this unique metal is widely used in biomedical fields. It is well known that pure magnesium has poor mechanical properties and the mechanical properties of magnesium can be effectively improved by the appropriate selection of alloying elements [1]. But, based on the aforementioned considerations, the range of alloying elements used in the degradable magnesium alloys is rather limited, Zn, Mn, Ca and perhaps a very small amount of low toxicity RE can be tolerated in the human body and can also be retard the biodegradation. Therefore, Mg-Ca binary alloys attract attention of researchers because Ca is an important element of human bones. The mechanical properties and biocompatibility of Mg-Ca binary alloy can be adjusted by controlling the Ca content and processing treatment. However, an inadequate mechanical properties as well as lower corrosion resistances of Mg-Ca binary alloys are the biggest drawback of these alloys [7][8]. Fortunately, in latest recent years, Mg-Zn system is paid more attention because Zn is one of abundant nutritional elements in human body [9] [10]. Additionally, it is a great potential