In this study, a specific Mg–Zn–RE alloy membrane with 6 wt.% zinc and 2.7 wt.% rare earth elements (Y, Gd, La and Ce) was prepared to investigate implant degradation, transport mechanism and guide bone regeneration in vivo. The Mg-membrane microstructure and precipitates were characterized by the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The Mg-membrane degradation process and effect on osteogenesis were investigated in a critical-sized rat calvarial defect model via micro-CT examination and hard tissue slicing after 2-, 5- and 8-week implants. Then, the distribution of elements in organs after 1-, 2- and 4-weeks implantation was examined to explore their transportation routes. Results showed that two types of precipitates had formed in the Mg–membrane after a 10-h heat treatment at 175 °C: γ-phase MgZn precipitation with dissolved La, Ce and Gd, and W-phase Mg₃(Y, Gd)₂Zn₃ precipitation rich in Y and Gd. In the degradation process of the Mg-membrane, the Mg matrix degraded first, and the rare earth-rich precipitation particles were transferred to a more stable phosphate compound. The element release rate was dependent on the precipitate type and composition. Rare earth elements may be transported mainly through the lymph system. The defects were repaired rapidly by the membranes. The Mg-membrane used in the present study showed excellent biocompatibility and enhanced bone formation in the vicinity of the implants.

中文翻译：

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Mg-Zn-RE合金膜在大鼠大颅盖缺损中的降解行为，转运机制和成骨活性

在这项研究中，准备了一种特殊的Mg-Zn-RE合金膜，其中含有6 wt。％的锌和2.7 wt。％的稀土元素（Y，Gd，La和Ce），以研究植入物的降解，转运机理并指导骨骼再生。体内。通过扫描电子显微镜（SEM）和透射电子显微镜（TEM）对镁膜的微观结构和析出物进行表征。在2周，5周和8周植入后，通过显微CT检查和硬组织切片，在临界大小的大鼠颅骨缺损模型中研究了Mg膜的降解过程及其对成骨的影响。然后，检查了植入1、2和4周后器官中元素的分布，以探讨它们的运输途径。结果表明，经过175°C的10 h热处理后，Mg-膜中形成了两种沉淀物：₃（Y，Gd）₂ Zn ₃沉淀物中富含Y和Gd。在Mg膜的降解过程中，Mg基质先降解，然后将富含稀土的沉淀颗粒转移到更稳定的磷酸盐化合物中。元素释放速率取决于沉淀物的类型和组成。稀土元素可能主要通过淋巴系统转运。缺陷被膜迅速修复。本研究中使用的Mg膜在植入物附近显示出极好的生物相容性并增强了骨形成。