Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: Poster: Interfaces and Thin Films (joint session with DECHEMA and VDI)
CPP 9.24: Poster
Montag, 11. März 2013, 17:30–19:30, Poster C
Effects of Reactive Oxygen Species on Phosphatidylglycerol Monolayer with Adsorbed Polyethylenimine — •Andreas Gröning1, Heiko Ahrens1, Frank Lawrenz1, Thomas Ortmann1, Fritz Scholz2, and Christiane A. Helm1 — 1Inst. für Physik, Uni Greifswald, Felix-Hausdorff-Str. 6, D-17487 Greifswald — 2Inst. für Biochemie, Uni Greifswald, D- 17487 Greifswald
Polymer adsorption is widely used to modify surfaces. To investigate the protective effect against free oxygen radicals polyethylenimine (PEI) is adsorbed onto oppositely charged DMPG lipid monolayers at the air/water interface. The structure of the lipid-polyelectrolyte system is investigated with X-ray reflectivity and grazing incidence diffraction. At different pH-values and mixed with a variety of salts PEI adsorbs flatly (2.8 nm). But in the presence of Fe(II)SO4 and EDTA in the solution a 15nm thick PEI layer is formed due to incorporation of Fe2+ EDTA complexes. Radical oxygen species are produced via the Fenton’s reaction. The reaction is started by H2O2 injection. If a highly compressed monolayer is attacked, the lateral pressure is reduced by 10mN/m within 30min for thin and 3h for thick adsorbed PEI layers. With X-ray reflectivity it is observed that the PEI layer shrinks and eventually disappears. Simultaneously, Fe2+ binds to the lipid monolayer and the solid lipid phase changes from NN-tilted to hexagonal.