Magnesium (Mg) is a potential alternative for conventional orthopaedic implant materials owing to its biodegradation behavior and physical characteristics similar to natural human bone. Due to its biomimetic mechanical attributes, Mg in orthopaedic applications could reduce the risk of the ‘stress shielding effect’. However, the major limitation of Mg is its high in-vivo corrosion rate. Thermal sprayed coatings of osteoconductive ceramics like hydroxyapatite (HA) have been explored as a potential solution, albeit with limited success due to the low melting point of Mg, which restricts the ease of fabricating surface-adherent ceramic coating. The present study focuses on overcoming this limitation through a Mg-HA functionally gradient material (FGM) system, which is expected to provide a highly corrosion-resistant surface and uniform mechanical integrity throughout the structure. In addition to corrosion resistance, the FGM system has improved biocompatibility and osteoconductivity without compromising its mechanical stability. The FGM, with a compositional gradient of Mg-HA composite, consisting of Mg at the core and increasing HA towards the outer layer, has been fabricated through spark plasma sintering. Mechanical properties of the overall structure were better than those of the best individual composite. More importantly, corrosion resistance of the FGM structure was significantly improved (~154%) as compared to individual composites. In addition, alkaline phosphatase activity, osteogenic gene expression and cell viability, all pertaining to efficient osteogenic differentiation, were enhanced for FGM and 15 wt% HA reinforced composites. These observations suggest that the FGM structure is promising for temporary biodegradable orthopaedic implants.

镁 (Mg) 是传统骨科植入材料的潜在替代材料，因为它具有与天然人体骨骼相似的生物降解行为和物理特性。由于其仿生机械属性，镁在骨科应用中可以降低“应力屏蔽效应”的风险。然而，Mg 的主要限制是其高体内腐蚀速率。诸如羟基磷灰石 (HA) 等骨传导陶瓷的热喷涂涂层已被探索为一种潜在的解决方案，尽管由于 Mg 的低熔点限制了制造表面粘附陶瓷涂层的容易性，但成功有限。本研究的重点是通过 Mg-HA 功能梯度材料 (FGM) 系统克服这一限制，该系统有望在整个结构中提供高度耐腐蚀的表面和均匀的机械完整性。除了耐腐蚀性之外，FGM 系统还提高了生物相容性和骨传导性，而不会影响其机械稳定性。通过放电等离子烧结制造了具有 Mg-HA 复合材料组成梯度的 FGM，其核心由 Mg 组成，向外层增加 HA。整体结构的力学性能优于最好的单个复合材料。更重要的是，与单个复合材料相比，FGM 结构的耐腐蚀性显着提高（~154%）。此外，对于 FGM 和 15 wt% HA 增强复合材料，碱性磷酸酶活性、成骨基因表达和细胞活力都与有效成骨分化有关。这些观察结果表明，FGM 结构有望用于临时可生物降解的骨科植入物。对于 FGM 和 15 wt% HA 增强复合材料，成骨基因表达和细胞活力都与有效成骨分化有关。这些观察结果表明，FGM 结构有望用于临时可生物降解的骨科植入物。对于 FGM 和 15 wt% HA 增强复合材料，成骨基因表达和细胞活力都与有效成骨分化有关。这些观察结果表明，FGM 结构有望用于临时可生物降解的骨科植入物。