稀土（RE）包括15种镧系元素、Sc和Y。检索全球医用Mg-RE合金文章，查到7种RE的二元镁合金和WE43、LAE442等多元镁合金，但RE添加量不同，材料制备加工方法不同，生物相容性评价条件不同，使得文献报导的Mg-RE合金之间生物相容性数据缺乏可比较性，还有多种RE未见报导。项目拟分别加入相同剂量RE（Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu）到Mg，按照同样的熔炼方法和加工路径，制得两类组织模型的Mg-RE二元合金（固溶有RE的Mg单相、Mg基体+第二相的双相），在等同试验条件下开展降解行为和体内外生物相容性等方面的对比性研究，以期获得16种RE与Mg制得的Mg-RE二元合金其降解产物引发细胞毒性、血液相容性、组织相容性的排序，为高性能Mg-RE合金设计的元素选择，即RE的种类、用量和适用的组织部位（骨或血液），提供指导性原则。

Rare earth (RE) elements include 15 lanthanides in periodic table of elements, and elements scandium and yttrium whose characteristics are similar to lanthanides. Currently, the reported research works on Mg-RE based alloys for biomedical application were limited, including seven binary alloy systems and WE43, LAE442 and other multi-component alloy systems. Due to the different addition content of the RE element, different material fabrication and process technology, and different experimental condition at biocompatibility evaluation, the in vitro and in vivo biocompatibility evaluation results on these materials are dispersive, without comparable and systematic data. Some RE elements are unknown. The present work aims to add the same amount of rare earth elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) into magnesium, respectively, to obtain binary Mg-RE model alloys (two material models: one is the Mg solid solution with RE, the other is the dual phases with the Mg matrix and the secondary phase ), with the same fabrication method and processing technology. Under the same experiment conditions, comparative study on the degradation behavior in simulated body fluid, cytotoxicity and biological evaluation after implantation in animals will be carried out to acquire the order of cytotoxicity and histocompatibility under the condition of co-release of a certain rare earth element and magnesium ion. The element optimization principle for designing Mg-RE alloys, which refers to the best choice of element type and additive content, and the suitable implantation position (within bone or blood vessel) for these 16 kinds of rare earth elements, will be concluded from the viewpoint of biocompatibility. The relevance of in vivo and in vitro measurement data will be determined, which will provide scientific guidance for high performance Mg-RE alloy implant materials and their medical device design.