Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 24: Posters: Membranes and vesicles
BP 24.4: Poster
Tuesday, March 17, 2015, 14:00–16:00, Poster A
How perfluorooctanoic acid inserts into a biomimetic model membrane — •Beate-Annette Brüning1,2, Martin Kreuzer1,3, and Roland Steitz1 — 1Helmholtz-Zentrum Berlin, Berlin, Germany — 2Delft University of Technology, Delft, Netherlands — 3Catalan Institute of Nanoscience and Nanotechnology, Barcelona, Spain
Perfluorinated compounds are found as biproducts of a wide range of industrial products. Upon entering cellular membranes, the compounds are known to cause developmental and reproductive disorders. We mimick the bioaccumulation in these membranes by inserting the perfluorinated surfactant PFOA into a DMPC phospholipid bilayer. We study changes in the membrane interface structure by X-ray diffraction and neutron reflectometry. We discuss our findings in the light of varying scattering contrasts: taking advantage of the C/F-contrast using X-ray diffraction, we probe the insertion of the perfluorinated surfactant into the phospholipid bilayer interior. We further observe changes in the thickness of the inter-bilayer hydration water layer using neutron reflectivity and H2O/D2O exchange. The combined X-ray and neutron scattering experiment suggests two main effects of PFOA-insertion into the membrane: i) changes in lipid acyl chain ordering combined with bilayer leaflet approximation, ii) 'drying' of the membrane (thinning of hydration water layer). We discuss, how both effects could contribute to a previously observed rigidification of the membrane through the perfluorooctanoic acid [1].
[1] B. Brüning and B. Farago; Perfluorooctanoic acid rigidifies a model lipid membrane; Physical Review E 89, 040702(R) (2014).