Sr对Zn-Sn基可降解生物医学合金微观结构与性能的影响

Effects of Sr on Microstructure and Properties of Zn-Sn-based Degradable Biomedical Alloys

摘要:

研究了可生物降解Zn-1.5Sn-xSr合金（x=0、0.3、0.5， wt%）的微观结构、力学性能、腐蚀行为及细胞毒性。结果表明，Sr元素的引入形成了微量SrZn₁₃相，提高了Zn-1.5Sn-xSr合金的屈服强度和弹性模量。通过透射电子显微镜衍射斑点标定，证明了SrZn₁₃相的存在。电化学测试证实了Zn-1.5Sn-xSr合金表面生成钝化膜，且Zn-1.5Sn-0.3Sr表现出更好的耐蚀性，进一步的浸泡测试与X射线光电子能谱分析揭示了腐蚀产物膜的元素组成及成分，主要由氧化物、氢氧化物以及微溶性碳酸盐和磷酸盐组成。在细胞毒性方面，Zn-1.5Sn-xSr合金表现出优异的生物相容性。MTT实验显示细胞活力最高可达130%，这归因于材料降解过程中Sr²⁺的释放，Sr²⁺与Zn²⁺共同促进了细胞增殖与分化。

Abstract:

The microstructure, mechanical properties, corrosion behavior, and cytotoxicity of biodegradable Zn-1.5Sn-xSr alloys (x=0, 0.3, 0.5, wt%) were investigated. The results indicate that the addition of Sr introduces minor SrZn₁₃ phases, enhancing the yield strength and elastic modulus of the Zn-1.5Sn-xSr alloys. Transmission electron microscopy analysis reveals the existence of the SrZn₁₃ phase through the calibration of diffraction spots. Electrochemical tests confirm the formation of a passive film on Zn-1.5Sn-xSr alloys, with Zn-1.5Sn-0.3Sr alloy exhibiting higher corrosion resistance. Further immersion tests and X-ray photoelectron spectroscopy analysis elucidate the elemental composition and content of the passive film formed by the corrosion products, which primarily consists of oxides, hydroxides, and slightly soluble carbonates and phosphates. In terms of cytotoxicity, the Zn-1.5Sn-xSr alloys exhibit excellent biocompatibility. MTT experiments show that the cell viability can reach up to 130%, which is attributed to the release of Sr²⁺ during the degradation. Sr²⁺ and Zn²⁺ ions jointly promote the cell proliferation and differentiation.