Protein adsorption on ZnO films studied by ATR-FTIR spectroscopy

In many scientific fields there is a high interest to study molecular adsorption processes on surfaces. The adsorbed molecule can have significant impact on the properties of the material under study, for example protein adsorption to inorganic material can enhance its biocompatibility. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy is a suitable method to monitor such adsorption processes close to a surface. In this study, ZnO films were synthesized on silicon ATR substrates via a mild hydrothermal reaction. The films were then characterized by scanning electron microscopy (SEM) and FTIR microscopy. Chemical imaging with FTIR microscopy allowed to analyze the composition of the heterogeneous film samples. ATR-FTIR spectroscopy was then applied to investigate the adsorption properties of the ZnO films. Protein solutions of bovine serum albumine (BSA) were circulated in a closed cycle over the ZnO film and IR spectra were recorded during the adsorption process. A stronger protein adsorption was observed for silicon substrates coated with ZnO than for plain silicon. Furthermore, subsequent flushing with pure water and desorption measurements indicated a stronger protein binding to ZnO than to plain silicon.publishe

Dispersion-corrected energy barriers for silylene addition to white phosphorus, a density functional investigation into substituent effects

Schoeller W. Dispersion-corrected energy barriers for silylene addition to white phosphorus, a density functional investigation into substituent effects. THEORETICAL CHEMISTRY ACCOUNTS. 2010;127(3):223-229.A density functional investigation into differently substituted silylenes with respect to the first step in the addition to white phosphorus is presented. The investigations include dispersion corrections in the density functional treatment. They become sizable for the transition state geometries for the silylenes as they become increasingly substituted by bulky groups. Hence, dispersion corrections are essential for a quantum chemical treatment of real molecules using density functional theory. The different singlet-triplet energy separations of differently substituted silylenes were also investigated and compared with calculated activation barriers for the first step in the addition reaction