Mao Genwen, Jin Xinxin, Sun Juan, Han Xuezhe, Zeng Min, Qiu Yusheng, Bian Weiguo
Department of Orthopedics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China.
Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China.
ACS Biomater Sci Eng. 2021 Jun 14;7(6):2755-2766. doi: 10.1021/acsbiomaterials.1c00218. Epub 2021 May 24.
Mg and its alloys have been comprehensively studied and show huge potential for clinical orthopedic applications. However, balancing the mechanical strength and corrosion resistance of alloys is still a challenge. In light of this, micro-level contents of Zn and Ca were added to pure Mg to fabricate a Mg-2Zn-0.05Ca microalloy to expectedly enhance the mechanical strength and concurrently improve the corrosion resistance. The characteristics of the rolled Mg-2Zn-0.05Ca microalloy were explored using optical microscopy, X-ray diffraction, and tensile tests. The corrosion behavior and mechanical strength loss were explored using electrochemical and immersion tests. The effects of the microalloy extract on the proliferation, adhesion, and osteogenic differentiation of MC3T3-E1 cells were systematically studied. Moreover, implantations were done in femoral condyles of rabbits to study the degradation properties, osteogenic effect, mechanical strength loss, and biosafety of the microalloy. The ultimate tensile strength and yield strength of the rolled microalloy were found to be significantly elevated to 257 ± 2.74 and 237.6 ± 8.29 MPa, respectively. The microalloy showed a stable and gradual strength loss during degradation, both and . Concurrently, the microalloy exhibited improved corrosion resistance ability and especially, , the rolled microalloy exhibited a comparable degradation rate to that of rolled pure Mg within the initial 12 weeks of implantation. Additionally, the microalloy promoted osteogenesis, both and , and no short- and long-term toxicities of the microalloy were observed in rabbits. This study suggested that the rolled Mg-2Zn-0.05Ca microalloy effectively balanced the mechanical strength and corrosion resistance and showed potential application as bone implants.
镁及其合金已得到全面研究，并在临床骨科应用中显示出巨大潜力。然而，平衡合金的机械强度和耐腐蚀性仍是一项挑战。鉴于此，向纯镁中添加微量的锌和钙，制备了Mg-2Zn-0.05Ca微合金，以期提高机械强度并同时改善耐腐蚀性。采用光学显微镜、X射线衍射和拉伸试验对轧制态Mg-2Zn-0.05Ca微合金的特性进行了探究。通过电化学和浸泡试验研究了其腐蚀行为和机械强度损失。系统研究了微合金提取物对MC3T3-E1细胞增殖、黏附和成骨分化的影响。此外，还将其植入兔股骨髁，以研究微合金的降解性能、成骨效果、机械强度损失和生物安全性。结果发现，轧制态微合金的极限抗拉强度和屈服强度分别显著提高至257±2.74和237.6±8.29MPa。微合金在降解过程中显示出稳定且逐渐的强度损失。同时，微合金的耐腐蚀性有所提高，特别是轧制态微合金在植入后的最初12周内，其降解速率与轧制态纯镁相当。此外，微合金促进了成骨，且在兔体内未观察到微合金的短期和长期毒性。本研究表明，轧制态Mg-2Zn-0.05Ca微合金有效地平衡了机械强度和耐腐蚀性，显示出作为骨植入物的潜在应用价值。
