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The biomodification of surfaces, especially titanium, is an important issue in current biomedical research. Regarding titanium, it is also important to ensure a specific protein modification of its surface because here protein binding that is too random can be observed. Specific nanoscale architectures can be applied to overcome this problem. As recently shown, streptavidin can be used as a coupling agent to immobilize biotinylated fibronectin (bFn) on a TiOX surface. Because of the conformation of adsorbed biotinylated fibronectin on a streptavidin monolayer, it is possible to adsorb more streptavidin and biotinylated fibronectin layers. On this basis, an alternating protein multilayer can be built up. In contrast to common layer-by-layer technology, in this procedure the mechanism of layer adsorption is very specific because of the interaction of biotin and streptavidin. In addition, we showed that the assembly of this multilayer system and its stability are dependent on the degree of labeling of biotinylated fibronectin. Hence we conclude that it is possible to build up well-defined nanoscale protein architectures by varying the degree of labeling of biotinylated fibronectin.
To achieve high temperature stable insulation materials for the electrical insulation of fine copper wires two different bis(alkoxysilylalkyl)pyromellitamide acids 1 and 2 were prepared. These organic–inorganic sol–gel hybrid precursors were obtained via reactions of pyromellitic dianhydride and alkoxysilylalkylamines. The molecular single-source precursors 1 and 2 were comprehensively studied using FT-IR, 1H, 13C and 29Si NMR spectroscopy as well as elemental analyses. Besides, the hydrolysis and condensation processes of the different precursors were examined with solution 29Si NMR spectroscopy. The imidization process was investigated using 13C NMR spectroscopy, FT-IR spectroscopy as well as thermal analysis methods. The different precursors were applied to coat fine copper wires using an industrial coating device. The obtained coatings were cured at temperatures between 380 and 425 °C, and tested regarding thicknesses, number of pinholes, electrical breakdown voltage and elongation. FT-IR spectroscopy was used to determine the chemical structure and scanning electron microscopy to investigate the morphology of the coating materials. The obtained coatings showed very promising mechanical, thermal and electrical properties, i.e. highest breakdown voltage values well above 200 V/µm. They possess high flexibility without cracking and no pinholes or other defects were detected.