Shunmugasamy Vasanth C, AbdelGawad Marwa, Sohail Muhammad Umar, Ibrahim Talal, Khan Talha, Seers Thomas Daniel, Mansoor Bilal
Mechanical Engineering Program, Texas A&M University at Qatar, Education City, Doha, Qatar.
Department of Mechanical Engineering, Texas A&M University, 3123 TAMU, College Station, TX 77843, USA.
Bioact Mater. 2023 Jun 24;28:448-466. doi: 10.1016/j.bioactmat.2023.06.010. eCollection 2023 Oct.
Magnesium alloys containing biocompatible components show tremendous promise for applications as temporary biomedical devices. However, to ensure their safe use as biodegradeable implants, it is essential to control their corrosion rates. In concentrated Mg alloys, a microgalvanic coupling between the α-Mg matrix and secondary precipitates exists which results in increased corrosion rate. To address this challenge, we engineered the microstructure of a biodegradable Mg-Zn-RE-Zr alloy by friction stir processing (FSP), improving its corrosion resistance and mechanical properties simultaneously. The FS processed alloy with refined grains and broken and uniformly distributed secondary precipitates showed a relatively uniform corrosion morphology accompanied with the formation of a stable passive layer on the alloy surface. In vivo corrosion evaluation of the processed alloy in a small animal model showed that the material was well-tolerated with no signs of inflammation or harmful by-products. Remarkably, the processed alloy supported bone until it healed till eight weeks with a low in vivo corrosion rate of 0.7 mm/year. Moreover, we analyzed blood and histology of the critical organs such as liver and kidney, which showed normal functionality and consistent ion and enzyme levels, throughout the 12-week study period. These results demonstrate that the processed Mg-Zn-RE-Zr alloy offers promising potential for osseointegration in bone tissue healing while also exhibiting controlled biodegradability due to its engineered microstructure. The results from the present study will have profound benefit for bone fracture management, particularly in pediatric and elderly patients.
含有生物相容性成分的镁合金作为临时生物医学装置具有巨大的应用前景。然而，为确保其作为可生物降解植入物的安全使用，控制其腐蚀速率至关重要。在高浓度镁合金中，α-Mg基体与二次析出物之间存在微电偶耦合，这会导致腐蚀速率增加。为应对这一挑战，我们通过搅拌摩擦加工（FSP）对一种可生物降解的Mg-Zn-RE-Zr合金的微观结构进行了设计，同时提高了其耐腐蚀性和力学性能。经搅拌摩擦加工的合金具有细化的晶粒以及破碎且均匀分布的二次析出物，呈现出相对均匀的腐蚀形态，合金表面形成了稳定的钝化层。在小动物模型中对加工后的合金进行体内腐蚀评估表明，该材料耐受性良好，没有炎症迹象或有害副产物。值得注意的是，加工后的合金在骨愈合直至八周的时间内都能支撑骨骼，体内腐蚀速率低至0.7毫米/年。此外，我们分析了肝脏和肾脏等关键器官的血液和组织学情况，结果显示在整个12周的研究期间，这些器官功能正常，离子和酶水平保持一致。这些结果表明，加工后的Mg-Zn-RE-Zr合金在骨组织愈合中的骨整合方面具有广阔的潜力，同时由于其设计的微观结构还表现出可控的生物降解性。本研究结果将对骨折治疗，特别是儿科和老年患者的骨折治疗产生深远的益处。
