Phase Transition of Individually Addressable Microstructured Membranes Visualized by Imaging Ellipsometry
| Autor: | Simon Faiss, Steffen Schuy, Claudia Steinem, Daniela Weiskopf, Andreas Janshoff |
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| Rok vydání: | 2007 |
| Předmět: |
Phase transition
Materials science Bilayer Vesicle Lipid Bilayers Temperature Analytical chemistry Microscopy Atomic Force Thermotropic crystal Phase Transition Surfaces Coatings and Films Diffusion chemistry.chemical_compound Membrane chemistry Ellipsometry Phosphatidylcholine Materials Chemistry Physical and Theoretical Chemistry Lipid bilayer |
| Zdroj: | The Journal of Physical Chemistry B. 111:13979-13986 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp073671t |
| Popis: | The phase transition of individually addressable microstructured lipid bilayers was investigated by means of imaging ellipsometry. Microstructured bilayers were created on silicon substrates by micromolding in capillaries, and the thermotropic behavior of various saturated diacyl phosphatidylcholine (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dipentadecoyl-sn-glycero-3-phosphocholine, and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)) bilayers as well as DMPC/cholesterol membranes was determined by measuring the area expansion and thickness of the bilayer as a function of temperature. We found an increase in the main phase transition temperature T(M) of 2-6 degrees C and a substantially reduced cooperativity compared to multilamellar vesicles. Measurements of lateral diffusion constants D employing fluorescence recovery after photobleaching revealed, however, only a marginal decrease in D compared to those found for vesicles and multibilayers. The known dependencies of T(M) both on the chain length of diacyl PC membranes and on the cholesterol content were reproduced on a solid support. Microstructured bilayers offer the unique advantage of integrating an internal standard of known thermotropic properties, which turned out to be important for reducing the measurement error and for ruling out the slightly changing impact of the surface on the phase transition behavior due to the surface pretreatment. |
| Databáze: | OpenAIRE |
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