The investigation of solid-liquid interfaces is one of the important areas of modern research. In particular, the adsorption of proteins and nanoparticles on liquid and solid surfaces is in the focus of actual research [1-4]. For example, solid-liquid interfaces occur on implants in the human body or in production facilities in food industry. The study of the adsorption of proteins is in so far important as adsorbed proteins can initiate the formation of biofilms, which is usually resulting in unwanted consequences [5]. A biofilm on an implant surface may support the growth of bacteria, so that the risk of an inflammatory reaction rises [6]. To decrease the risk of inflammatory reactions, titanium dioxide is widely used as an implant material, since both the surface of titanium dioxide is one of the most biocompatible ones among suitable implant materials as well as it shows other favorable features [7].
Here, the use of high energy x-rays allows the analysis of buried interfaces in-situ by reflectivity measurements. High resolution electron density profiles from the solid-liquid interface can be obtained by means of x-ray reflectivity measurements, giving information about layer properties, such as layer thickness, roughness and electron density. Lysozyme has been chosen as a model protein, since the adsorption behavior of lysozyme on silicon substrates has already been investigated by our group [2-3] and thus can be compared to studies on titanium dioxide.
We investigated the adsorption behavior of lysozyme on a TiO2-coated silicon wafer as a function of temperature and pressure by means of x-ray reflectivity. First electron density profiles from the solid-liquid interface between titanium dioxide and the lysozyme solution will be shown, discussed and compared to similar XRR studies on silicon dioxide wafers.