Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Interfaces
CPP 35.4: Vortrag
Freitag, 29. Februar 2008, 11:30–11:45, C 130
Polarisation modulation IR studies on silica surfaces functionalised with protein resistant coatings — •Stefan Zorn1, Iain Dunlop2, Alexander Gerlach1, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, Germany — 2Max Planck Institut für Metallforschung, Stuttgart, Germany
We performed polarisation modulation infrared reflection absorption spectroscopy (PM-IRRAS) studies of organic silane coatings on silica surfaces and their protein resistance. PM-IRRAS measurements require conducting surfaces to get a signal and to benefit from the surface selection rules. In the case of silane chemistry an important tool to functionalise silicon and glass surfaces this is hardly possible. We developed a multilayer, consisting of a titanium layer and a sputtered silica layer on top which is easy to produce and enables us to perform PM-IRRAS measurements on silanised surfaces. We studied biotinylated PEG2000 layers, a widely used system for sensor surfaces, and their ability to resist unspecific protein binding and enables specifically streptavidin binding. We were able to demonstrate PEG adsorption on the substrates and the specific binding of streptavidin with characteristic absorption modes. We also discuss theoretical aspects of the signal on different layer systems with the help of simulations based on the Fresnel equations.