Magnesium-based biomaterials have been in extensive research for orthopedic applications for decades due to their optimal mechanical features and osteopromotive nature; nevertheless, rapid degradation restricts their clinical applicability. In this study, pristine magnesium was purified (P-Mg) using a melt self-purification approach and reinforced using indigenously synthesized nanohydroxyapatite (HAP, 0.6 wt.%) and strontium substituted nanohydroxyapatite (SrHAP, 0.6 wt.%) using a low-cost stir assisted squeeze casting method to control their degradation rate. Using electron back-scattered diffraction (EBSD) and X-ray diffraction (XRD) examinations, all casted materials were carefully evaluated for microstructure and phase analysis. Mechanical characteristics, in vitro degradation, and in vitro biocompatibility with murine pre-osteoblasts were also tested on the fabricated alloys. For in vivo examination of bone formation, osteointegration, and degradation rate, the magnesium-based alloys were fabricated as small cylindrical pins with a diameter of 2.7 mm and a height of 2 mm. The pins were implanted in a critical-sized defect in a rat femur shaft (2.7 mm diameter and 2 mm depth) for 8 weeks and evaluated by micro-CT and histological evaluation for bone growth and osteointegration. When compared to P-Mg and P-MgHAP, micro-CT and histological analyses revealed that the P-MgSrHAP group had the highest bone formation towards the periphery of the implant and hence maximum osteointegration. When the removed pins from the bone defect were analyzed using GIXRD, they displayed hydroxyapatite peaks that were consistent with bio-integration. For P-Mg, P-MgHAP, and P-MgSrHAP 8 weeks after implantation, in vivo degradation rates derived from micro-CT were around 0.6 mm/year, 0.5 mm/year, and 0.1 mm/year, respectively. Finally, P-MgSrHAP possesses the requisite degradation rate as well as sufficient mechanical and biological properties, indicating that it has the potential to be used in the development/fabrication of biodegradable bioactive orthopaedic implants.

几十年来，镁基生物材料因其最佳的机械特性和促骨性质而在骨科应用方面进行了广泛的研究；然而，快速降解限制了它们的临床应用。在这项研究中，使用熔体自净化方法纯化原始镁 (P-Mg)，并使用低-成本搅拌辅助挤压铸造方法来控制它们的降解速率。使用电子背散射衍射 (EBSD) 和 X 射线衍射 (XRD) 检查，所有铸造材料都经过仔细评估以进行微观结构和相分析。机械特性，体外降解，体外还在制造的合金上测试了与小鼠前成骨细胞的生物相容性。对于体内为了检查骨形成、骨整合和降解率，将镁基合金制成直径为 2.7 毫米、高度为 2 毫米的小圆柱销。将针植入大鼠股骨干（直径 2.7 毫米，深度 2 毫米）的临界尺寸缺损处 8 周，并通过显微 CT 和组织学评估骨生长和骨整合进行评估。与 P-Mg 和 P-MgHAP 相比，显微 CT 和组织学分析表明，P-MgSrHAP 组在种植体周边具有最高的骨形成，因此具有最大的骨整合。当使用 GIXRD 分析从骨缺损处移除的针时，它们显示出与生物整合一致的羟基磷灰石峰。对于植入后 8 周的 P-Mg、P-MgHAP 和 P-MgSrHAP ，在体内来自显微 CT 的降解率分别约为 0.6 毫米/年、0.5 毫米/年和 0.1 毫米/年。最后，P-MgSrHAP 具有必要的降解速率以及足够的机械和生物学特性，表明它有可能用于开发/制造可生物降解的生物活性骨科植入物。