0000000000699647
AUTHOR
G. Brezesinski
Morphology and structures in double-, triple- and quadruple-chain phospholipid monolayers at the air/water interface
The structure of double-, triple- and quadruple-chain phospholipid monolayers has been studied by Synchrotron x-ray diffraction. The double-chain mixed- linkage species exhibit an oblique structure at all pressures investigated. The triple-chain phospholipids show at lower lateral pressures a rectangular unit cell with a phase transition at higher pressures to a hexagonal packing of vertically arranged chains. The quadruple- chain lipid exhibits only the hexagonal phase structure. The position of the ether linkage and of the branched chain on the glycerol backbone has also a strong influence on the monolayer structures. Fluorescence microscopy shows different domain shapes for the different…
Polymorphic domains in monolayers of isomeric triple-chain phospholipids
Monolayers of two isomeric branched chain phosphatidyl cholines at the air/water interface have been studied by means of fluorescence microscopy. The lipids differ in the position of the branched chain at the glycerol backbone and carry three chains per headgroup of almost equal length. Most qualitative features of the compression isotherms are similar except a difference of 4 A2/molecule in the minimum molecular area at high lateral pressures. This indicates a more condensed solid phase of compound C2 and is also reflected in the shapes of domains observed in the LE/LC phase coexistence range: domains with sharp edges and a mostly hexagonal shape are formed. On the other hand, the compound…