Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 23: Interfaces and Thin Films I (joint session CPP, DS)

CPP 23.8: Talk

Tuesday, March 17, 2015, 12:00–12:15, C 243

Pressure induced adsorption of lysozyme at the solid-liquid interface — •Paul Salmen¹, Julia Nase¹, Susanne Dogan¹, Holger Göhring¹, Irena Kiesel^1,3, Johannes Möller^1,2, Christopher Weis¹, Florian Wirkert¹, Michael Paulus¹, and Metin Tolan¹ — ¹Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany — ²ESRF - The European Synchrotron, 71 Avenue des Martyrs, F-38043 Grenoble, France — ³Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France

The pressure-induced adsorption of proteins at hydrophilic and hydrophobic interfaces was studied by x-ray reflectivity measurements. In our custom-built cell for x-ray reflectivity (XRR) measurements [1], we are able to apply pressures up to 5 kbar and study the solid/liquid interface in-situ with Angstrom resolution. As hydrophobic surfaces, silicon wafers covered with octadecyltrichlorosilane (OTS) were used, while bare silicon wafers with a native silicon dioxide layer provide charged, hydrophilic interfaces. Lysozyme was used in 20 mM BisTris buffer (pH 7.1) at a concentration of 0.1 mg/ml. The measurements were performed at the synchrotron light sources DELTA (Dortmund, Germany), ESRF (Grenoble, France) and SLS (Villigen, Switzerland) using high energy x-ray radiation. At low pressures, only a monolayer of lysozyme adsorbs at both interfaces. When pressure is increased, a second layer of lysozyme adsorbs. Because the thickness of the first layer decreases in this process, we suppose a partial collapse of the first lysozyme layer. [1] F. J. Wirkert et al., Journal of Synchrotron Radiation 2014 (21) doi:10.1107/S1600577513021516