Phospholipid monolayers between fluid and solid states.

C A Helm; H Möhwald; K Kjaer; J Als-Nielsen

doi:10.1016/s0006-3495(87)83226-5

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Phospholipid monolayers between fluid and solid states.

C A Helm·H Möhwald·K Kjaer·J Als-Nielsen

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Abstract

Monolayers of the phospholipid dimyristoyl phosphatidic acid on the surface of water have been studied by a combination of the new techniques of synchrotron x-ray diffraction and fluorescence microscopy with classical surface pressure data. The pressure vs. area isotherm changes slope at the surface pressures pi c and pi s. The optical technique demonstrates that between pi c and pi s the fluid phase coexists with a denser "gel" phase. Electron diffraction data have shown that the gel phase has bond orientational order over tens of micrometers. However, the x-ray data demonstrate that positional correlations extend only over tens of angstroms. Thus, the gel phase is not crystalline. Above pi s a solid phase is formed with a positional correlation range that is eight times longer for the chemically purest films.

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Glycerophospholipids Liposomes Microscopy, Fluorescence Models, Biological Molecular Conformation Phosphatidic Acids Thermodynamics X-Ray Diffraction Journal Article Research Support, Non-U.S. Gov't

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C A Helm, H Möhwald, K Kjaer, J Als-Nielsen. 1987. Phospholipid monolayers between fluid and solid states.. https://doi.org/10.1016/s0006-3495(87)83226-5

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