Influence of nanopatterend titanium surfaces on the osteogenic differentiation of human mesenchymal stem cells in combination with chemical and biological surface modifications (NanoTune)

各向异性，有序的表面形貌在低纳米水平上的人骨髓间充质干细胞（hMSC）的行为的影响，迄今为止还没有得到充分的研究和了解。然而，具有低于10 nm范围的垂直尺寸和大约几个10 nm的横向尺寸的形貌表现出显著影响细胞附着和成骨承诺的高潜力，特别是与定制的化学和生物化学表面修饰相结合。因此，本研究的目的是调查的假设，这种纳米结构的钛基板上可以显着影响蛋白质吸附以及hMSC的粘附，迁移和成骨分化，无论是通过自己和放大与化学和生物表面修饰。低能离子轰击将用于产生具有几十纳米的横向周期和高度在< 1 nm至5 nm范围内的有序波状涟漪图案。随后，定制的表面化学将通过硅烷化产生，交联将用于特异性地偶联两种蛋白质，玻连蛋白和纤连蛋白，其在细胞粘附、迁移和分化中起主要作用。此外，还将使用QCM-D、AFM和PM-IRRAS等以及免疫细胞化学测定法研究未改性的以及化学多样化的表面非特异性吸附蛋白质的能力。随后将使用已建立的粘附、迁移和分化测定来表征接种的hMSC的表面诱导的细胞应答。地形，化学和生物化学参数，然后将系统地改变，以揭示各自的影响，对细胞的个别表面改性。为此，将对hMSC的形态、细胞组成和重组、增殖和分化行为进行广泛的体外分析。因此，本研究中收集的关于干细胞对低纳米水平基底形貌的反应的数据将有助于改善未来的设计和可用性，例如骨科和牙科植入物。

The influence of anisotropic, ordered surface topographies at the low nanometer level on the behavior of human mesenchymal stem cells (hMSC) is thus far insufficiently investigated and poorly understood. Yet topographies with vertical dimensions in the sub-10 nm range and lateral dimensions of the order few 10 nm exhibit high potential to significantly influence cellular attachment and osteogenic commitment, especially in combination with tailored chemical and biochemical surface modifications. This study therefore aims at investigating the hypothesis that such nanostructures on titanium substrates can significantly influence protein adsorption as well as hMSC adhesion, migration, and osteogenic differentiation, both by themselves and amplified with chemical and biological surface modifications. Low-energy ion bombardment will be used to generate ordered wave-like ripple patterns with lateral periodicities of few ten nanometers and heights in the range from < 1 nm to 5 nm. Subsequently, tailored surface chemistry will be generated by silanization, and crosslinking will be used to specifically couple two proteins, vitronectin and fibronectin, which play major roles in cell adhesion, migration, and differentiation. The unmodified as well as the chemically diversified surfaces will furthermore be investigated for their ability to unspecifically adsorb proteins, using QCM-D, AFM, and PM-IRRAS among others, as well as immunocytochemistry assays. Established adhesion, migration and differentiation assays will subsequently be used to characterize the surface induced cellular responses of the seeded hMSC. The topographical, chemical, and biochemical parameters will then be systematically varied to reveal the respective influences of the individual surface modifications on the cells. For this, extensive in-vitro analyses of the morphology, cellular composition and reorganization, proliferation, and differentiation behavior of the hMSC will be conducted. The data gathered within this study, regarding stem cell response to substrate topographies at the low-nanometer level, will thus be helpful to improve future design and availability of e.g. orthopaedic and dental implants.