Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 15: Postersession III
BP 15.7: Poster
Dienstag, 13. März 2018, 14:00–16:00, Poster B
Temperature Induced Structural Evolution of DMPC-Saponin-Mixtures: From Bicellar to Vesicular Structures — •Carina Dargel1, Aurel Radulescu2, and Thomas Hellweg2 — 1Bielefeld University, Germany — 2Jülich Center for Neutron Science, outstation at FRM II, Garching, Germany
Vesicles composed of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine are often used as model system to mimic cell membranes. The system allows to study effects of additives under different conditions, e.g. composition and temperature. Saponins are plant derived surfactants which occur among others in nuts and garlic and exhibit an amphiphilic structure built of a hydrophobic steroidic or triterpenic backbone with a varying number of hydrophilic sugar chains. For the saponin aescin an incorporation into the lipid bilayer was proven for low aescin amounts in a study with unilamellar vesicles. At low temperature and at aescin amounts higher than about 10 mol % the vesicles get solubilized into much smaller bicellar structures. By increasing temperature the bicelles convert into uni- and multilamellar vesicles due to removal of the saponin from the aggregates. These aggregates decompose again when lowering the temperature to about 23 ∘C, the main phase transition temperature of the phospholipid DMPC.
In this study the self-assembled structures are investigated in dependence on the aescin amount as well as the temperature mainly by dynamic light scattering and small angle neutron scattering to resolve the correlation between the lipids phase transition and the reconversion of the bicellar structures.