生物可降解锌合金用于骨植入物的研究进展

生物可降解锌合金是新型的具有发展前景的人体骨植入物材料。讨论了生物可降解锌合金在力学性能、腐蚀降解行为和生物相容性等方面作为骨植入物材料的开发潜力和应用前景。重点综述了近年来不同合金元素的选择和添加量对生物可降解锌合金的强韧化影响、生物可降解性及生物相容性评价。同时，讨论了塑性变形过程对生物可降解锌合金力学性能的影响。另外，还介绍了生物可降解锌合金的体内外降解行为、生物腐蚀机理、生物相容性及其要求。明确了各种增强手段对生物可降解锌合金的影响，并分析讨论了各种手段的可取与不足之处。针对当前制备技术存在的问题，结合已有研究成果，指明生物锌合金未来的发展方向。生物锌合金的强化方法，如合金化、改变添加量、变形加工操作、表面改性处理等，可以有效提高纯锌的综合性能。锌合金的降解速率适中，不产生氢气袋，降解产物能起到保护层的作用，有助于提高细胞黏附性，增强抗菌能力。锌合金的生物相容性与锌离子的释放量密切相关。制备ZnP涂层的表面改性技术能够有效降低锌离子释放量，进而改善生物相容性。目前，生物可降解锌合金在生物体植入物中已经取得部分进展，但是，其力学性能和生物相容性仍是较长一段时间内努力的方向，开发新的增强手段及体内动态模拟试验和性能评估方法也都是未来的重要发展趋势。

Research Progress of Biodegradable Zinc Alloys for Bone Implants

Biodegradable zinc alloy is a new and promising material for human bone implants. Its degradation rate conforms to the degradation rate standard of human implants and has good mechanical properties and biocompatibility. This paper briefly introduces the development potential and application prospects of biodegradable zinc alloys as bone implant materials in terms of mechanical properties, corrosion degradation behavior and biocompatibility. The effects of the selection and addition of different alloying elements on the toughening, biodegradability and biocompatibility evaluation of biodegradable zinc alloys in recent years are emphatically reviewed. At the same time, the effect of plastic deformation process on the mechanical properties of biodegradable zinc alloy was discussed. In addition, this overview also investigates the requirements of the in vitro and in vivo degradation behavior and biocorrosion mechanism of biodegradable zinc alloys, and briefly discusses the biocompatibility of biodegradable zinc alloys from the aspects of cell response, blood compatibility, tissue immunity. The effects of various enhancement methods on biodegradable zinc alloys are clarified, and the advantages and disadvantages of various methods are analyzed and discussed. In view of the problems existing in the current preparation technology, combined with the existing research results, the future development direction of bio-zinc alloys is pointed out. The enhancement methods of bio-zinc alloys, such as alloying, changing the addition amount, deformation processing operations, and surface modification treatments, can effectively improve the comprehensive properties of pure zinc. Alloying builds binary alloys or multi-component alloys, which play a role in fine-grain strengthening of the matrix and improve strength and hardness. The selection of the addition amount combined with comprehensive tests such as in vitro and in vivo experiments and biocompatibility tests show that the appropriate addition amount can induce osteoblast differentiation without causing cytotoxicity, but excessive additions such as Li, Al, Ag may cause a series of human disease. Deformation processing processes such as extrusion, cumulative extrusion, and cold drawing are strengthened by changing grain morphology and dynamic recrystallization, and the cumulative extrusion process can significantly enhance mechanical properties. It can be seen from the degradation behavior and corrosion mechanism in vitro and in vivo that the zinc alloy has a moderate degradation rate and does not generate hydrogen gas pockets. The degradation products can act as a protective layer, which helps to improve cell adhesion and enhance antibacterial ability. The osteogenic ability, serum level, and cell survival rate of zinc alloys implanted in organisms are closely related to the release of zinc ions. The amount of zinc ions released by zinc alloys is generally within the safe threshold range and will not cause cytotoxicity. Surface modification technology can further regulate the release of zinc ions. The preparation method of ZnP coating is simple, which is an effective means to reduce the release of zinc ions and can effectively improve the biocompatibility. At present, some progress has been made in biodegradable zinc alloys in biological implants. However, the mechanical properties and biocompatibility of biodegradable zinc alloys are still the direction of efforts for a long time. In the future, based on the advantages of the existing enhancement methods of biodegradable zinc alloys, the development of new enhancement methods and in vivo dynamic simulation tests and performance evaluation methods are all important development trends in the future.