Electrochemical nanostructuring of surfaces of bulk metallic glasses on Ti-Cu basis for improvement of their biocompatibility

Ti-Cu基大块金属玻璃由于具有较高的机械生物功能，在牙科和创伤外科领域被认为是一种有前景的骨植入材料。然而，与目前临床使用的材料相比，其生物相容性仍然不足。一个关键的方面是它们的高铜含量，这可能导致局部腐蚀现象，从而释放有毒物质和机械材料失效。此外，对于这些bmg，到目前为止还没有可靠的概念来产生生物活性表面状态，这是永久性植入物所必需的。本项目将研究多组分ti - cu基bmg表面的电化学纳米结构方法，以有效提高其生物相容性和腐蚀稳定性。该方法的目标是显著降低合金元素的浓度，这些元素是获得高玻璃形成能力所必需的，但对于生物相容性来说是至关重要的，来自近表面区域。同时，纳米多孔，主要是氧化表面结构将产生，以提高耐腐蚀性和刺激骨细胞的活性。bmg的机械性能不应受到显著影响。在该项目中，两种有前途的大块玻璃成形Ti-Cu合金正在进行研究，其铸造工艺已经在IFW Dresden建立。对于纳米结构，玻璃样品在无卤素酸溶液中主要采用阳极处理。从根本上研究了处理参数对发展表面状态的影响，并描述了潜在的表面反应机制。一个关键方面是分析这些表面状态对bmg在合成生理溶液中的腐蚀行为的影响。特别是，点蚀的敏感性是通过产生定制的氧化态来降低的。通过细胞生物学研究，我们将从根本上评估不同表面状态对人间充质间质细胞和牙周韧带成纤维细胞行为的影响。举例来说，对于一个选定的BMG，表面纳米结构对压缩和拉伸载荷下力学性能的影响将被评估。在这些研究的结果中，将描述ti - cu基bmg的结构和化学特性之间的基本关系，电化学表面纳米结构的衍生路线以及由此产生的腐蚀，机械和细胞生物学特性。

Owing to their high mechanical biofunctionality bulk metallic glasses (BMG) on Ti-Cu base are considered as prospective new materials for bone implants in the fields of dentistry and trauma surgery. However, in comparison to materials in current clinical use their biocompatibility is still insufficient. A critical aspect is their high Cu content, which can cause local corrosion phenomena and in consequence, the release of toxic species and mechanical material failure. Moreover, for those BMGs there are so far no reliable concepts for the generation of bioactive surface states which are mandatory for permanent implants. In the applied project a method for an electrochemical nanostructuring of surfaces of multicomponent Ti-Cu-based BMGs will be developed with the objective of effectively improving the biocompatibility and corrosion stability. The method is targeted on significantly reducing the concentration of alloying elements which are necessary for obtaining high glass-forming ability but which are critical with respect to biocompatibility, from near-surface regions. At the same time nanoporous, predominantly oxidic surface structures will be generated in order to improve the corrosion resistance and to stimulate the activity of bone cells. The mechanical performance of the BMGs must not be significantly affected. In the project two promising bulk glass-forming Ti-Cu alloys are subject of investigation for which the casting processes are already established at the IFW Dresden. For the nanostructuring, anodic treatments of glassy samples in halogenide-free acid solutions are primarily employed. The effects of treatment parameters on the developing surface states are fundamentally investigated and the underlying surface reaction mechanisms are described. A key aspect is the analysis of the impact of those surface states on the corrosion behaviour of the BMGs in synthetic physiological solutions. In particular the pitting corrosion susceptibility is to be reduced by the generation of tailored oxidic states. By means of cell biological studies the effect of selected surface states on the behaviour of human mesenchymal stroma cells (hBMSC) and of periodontal ligament fibroblasts will be fundamentally evaluated. Exemplarily, for one selected BMG the impact of surface nanostructuring on the mechanical properties under compression and tensile load will be assessed. In result of these studies, fundamental relations between structural and chemical particularities of the Ti-Cu-based BMGs, derivable routes for electrochemical surface nanostructuring and resulting corrosive, mechanical and cell biological properties will be described.