Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 12: Poster II

BP 12.42: Poster

Dienstag, 2. April 2019, 14:00–16:00, Poster B2

Mechanical parameters of phospholipid multi-layers from off-specular x-ray scattering — •Max Scheu, Tim Salditt, Kilian Frank, and Karlo Komorowski — Institut für Röntgenphysik, Göttingen

The structural analysis of phospholipid bilayers which exert a prominent role in different biological systems is of increasing importance for understanding processes such as membrane adhesion or fusion. In order to determine the continuum mechanical parameters namely compression and bending modulus of solid-supported phospholipid multi-layers different specular and off-specular x-ray scattering experiments were conducted. Via comparison to smectic elastic theory the results give insight to membrane dynamics as well as to potential pre-critical phenomena prior to the so-called stalk phase transition. We used a model with three free parameters, derived from membrane displacement correlation functions in the kinematic approximation of the scattering function, to describe stratified interfaces of membranes with correlated roughness. This model was used to simulate complete reciprocal space maps and extract the bending rigidity and the compression modulus from experimental data. In particular the structural changes of lamellar phases of different phospholipids, promoted by change in relative humidity or ionic environment, are evaluated by measurement and modeling in direct vicinity of bragg peaks. These findings may help to ascertain further insight on interaction potentials of membranes as well as transmembrane cellular medication uptake.