Shear Orientation of a Micellar Hexagonal Liquid Crystalline Phase: A Rheo and Small Angle Light Scattering Study

Langmuir ◽  
1994 ◽  
Vol 10 (11) ◽  
pp. 4374-4379 ◽  
Author(s):  
Walter Richtering ◽  
Joerg Laeuger ◽  
Reinhard Linemann
Keyword(s):  
Light Scattering ◽  
Small Angle ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Shear Orientation ◽  
Scattering Study ◽  
Small Angle Light Scattering

scholarly journals Formation of unilamellar dipalmitoylphosphatidylcholine vesicles promoted by Ca2+ions: A small-angle neutron scattering study

2007 ◽  
Vol 21 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Daniela Uhríková ◽  
José Teixeira ◽  
Adrián Lengyel ◽  
László Almásy ◽  
Pavol Balgavý
Keyword(s):  
Neutron Scattering ◽  
Lipid Bilayer ◽  
Small Angle ◽  
Crystalline Phase ◽  
Small Angle Neutron Scattering ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Bilayer Thickness ◽  
Unilamellar Vesicles ◽  
Gel Phase

Dipalmitoylphosphatidylcholine (DPPC) was hydrated in 0.2–60 mM solution of CaCl2in heavy water and thoroughly homogenized by freezing-thawing process. Small-angle neutron scattering (SANS) shows formation of unilamellar vesicles in the range 1–60 mM of CaCl2. From the Kratky–Porod plot ln [I(Q)Q2] vs.Q2of SANS intensityI(Q)in the range of scattering vectorsQcorresponding to the interval 0.001 Å−2≤Q2≤0.006 Å−2, the vesicle bilayer radius of gyrationRgand the bilayer thickness parameterdgwere obtained. The structure of the bilayer displays different behavior for the gel phase and the liquid-crystalline phase: In the gel phase (at 20°C), the values ofdgindicate nonlinear changes in the lipid bilayer thickness, with a maximum at ~5 mM CaCl2. In the liquid-crystalline phase (at 60°C), the parameter of the lipid bilayer thicknessdg=43.2±0.3 Å is constant within the concentration range 1≤cCa≤40 mM. Vesicles prepared at 60 mM CaCl2show within experimental error, the same values ofdgas pure DPPC unilamellar vesicles prepared by extrusion using polycarbonate filter with pores of diameter 500 Å.

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