Department of Physics, TU Dortmund University, Otto-Hahn-Str. 4a, Dortmund, 44227, Germany.
Department of Orthopedic Surgery, Rush University Medical Center, 1611 W. Harrison St., Chicago, 60612, IL, USA.
Acta Biomater. 2024 Nov;189:621-632. doi: 10.1016/j.actbio.2024.10.006. Epub 2024 Oct 9.
Modular hip implants are a clinically successful and widely used treatment for patients with arthritis. Despite ongoing retrieval studies the understanding of the fundamental physico-chemical mechanisms of friction and wear within the head-taper interface is still limited. Here, we Raman-spectroscopically analyze structural features of the biotribological material which is formed within the taper joint between Ti6Al4V and low-carbon cobalt alloy or high-nitrogen steel surfaces in in vitro gross-slip fretting corrosion tests with bovine calf serum. As a function of the fretting duration, we investigate short and long aliphatic chains and their adsorption behavior on the cobalt- and steel-type surfaces. Using the intensity and frequency shifts of the amide I and III Raman bands, we furthermore identify progressive protein folding and unfolding including the secondary structures of α-helix, β-sheet, and random-coil configuration as well as the formation of proteinaceous clusters depending on the hydrophilicity of the metallic surfaces. We additionally find a mixture of chromates and iron oxides with tryptophan and tyrosine at the worn cobalt alloy and high-nitrogen steel surfaces, respectively. Also, for long fretting duration, sp hybridized amorphous carbon is formed due to fretting-induced cleavage of proteins. STATEMENT OF SIGNIFICANCE: Despite efforts enhancing the biomedical tribology of hip implants, the impact of the organic environment on friction and wear at the femoral head-stem taper interface is limitedly understood. Using Raman spectroscopy we resolve structural changes within the biotribological material agglomerated at biomedical-grade metal alloys due to metal-organic interactions during in vitro fretting corrosion tests. Adsorption of short and long aliphatic chains, progressive protein (un)folding and proteinaceous cluster formation depend to a distinguishable extent on the fretting duration and type of alloy. Chromates and iron oxides are mixed with tryptophan and tyrosine, and amorphous carbon is formed resulting from a fretting-induced cleavage of serum proteins. Such information spectroscopically gleaned from biotribological material are vital to improve the design and performance of taper junctions.
模块化髋关节植入物是治疗关节炎患者的一种临床成功且广泛应用的治疗方法。尽管不断进行检索研究，但对于钛 6 铝 4 钒和低碳钴合金或高氮钢表面头锥接口内摩擦和磨损的基本物理化学机制的理解仍然有限。在这里，我们通过体外宏观滑动微动腐蚀试验，用牛犊血清分析了在 Ti6Al4V 和低碳钴合金或高氮钢表面的锥度接头内形成的生物摩擦学材料的结构特征。作为微动持续时间的函数，我们研究了短链和长链脂肪族链及其在钴和钢型表面上的吸附行为。通过酰胺 I 和 III 拉曼带的强度和频率位移，我们进一步确定了渐进的蛋白质折叠和展开，包括α-螺旋、β-折叠和无规卷曲构象的二级结构，以及根据金属表面的亲水性形成蛋白质簇。我们还在磨损的钴合金和高氮钢表面上分别发现了色氨酸和酪氨酸的铬酸盐和氧化铁混合物，以及由于摩擦诱导的蛋白质断裂而形成的 sp 杂化无定形碳。
尽管髋关节植入物的生物医学摩擦学得到了加强，但有机环境对股骨头-柄锥接口摩擦和磨损的影响理解有限。使用拉曼光谱，我们在体外微动腐蚀试验中，由于金属-有机相互作用，在生物摩擦学材料中解析了在生物医学级金属合金上聚集的结构变化。短链和长链脂肪族链的吸附、渐进的蛋白质（解）折叠和蛋白质簇的形成在很大程度上取决于微动持续时间和合金类型。色氨酸和酪氨酸与铬酸盐和氧化铁混合，由于血清蛋白的摩擦诱导断裂，形成无定形碳。从生物摩擦学材料中以这种方式获得的信息对于改进锥度接头的设计和性能至关重要。
