Phase Transition of Individually Addressable Microstructured Membranes Visualized by Imaging Ellipsometry
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- 作者：Simon Faiss ; Steffen Schuy ; Daniela Weiskopf ; Claudia Steinem ; Andreas Janshoff
- 刊名：Journal of Physical Chemistry B
- 出版年：2007
- 出版时间：December 20, 2007
- 年：2007
- 卷：111
- 期：50
- 页码：13979 - 13986
- 全文大小：571K
- 年卷期：v.111,no.50(December 20, 2007)
- ISSN：1520-5207
文摘
The phase transition of individually addressable microstructured lipid bilayers was investigated by means ofimaging 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 thearea expansion and thickness of the bilayer as a function of temperature. We found an increase in the mainphase transition temperature TM of 2-6 C and a substantially reduced cooperativity compared to multilamellarvesicles. Measurements of lateral diffusion constants D employing fluorescence recovery after photobleachingrevealed, however, only a marginal decrease in D compared to those found for vesicles and multibilayers.The known dependencies of TM both on the chain length of diacyl PC membranes and on the cholesterolcontent were reproduced on a solid support. Microstructured bilayers offer the unique advantage of integratingan internal standard of known thermotropic properties, which turned out to be important for reducing themeasurement error and for ruling out the slightly changing impact of the surface on the phase transitionbehavior due to the surface pretreatment.