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Gewählte Publikation:

Melzak, KA; Melzak, SA; Gizeli, E; Toca-Herrera, JL.
(2012): Cholesterol Organization in Phosphatidylcholine Liposomes: A Surface Plasmon Resonance Study
MATERIALS. 2012; 5(11): 2306-2325. FullText FullText_BOKU

Abstract:
Models for the organization of sterols into regular arrays within phospholipid bilayers have been proposed previously. The existence of such arrays in real systems has been supported by the fact that concentration-dependent sterol properties show discontinuities at the cholesterol mole fractions corresponding to regular lattice arrangements. Experimental results presented here are based on a surface plasmon resonance assay that was used to analyze rates of cyclodextrin-mediated removal of cholesterol from adsorbed liposomes at cholesterol mole fractions up to chi(C) = 0.55. Two kinetic pools of cholesterol were detected; there was a fast pool present at chi(C) > 0.25, and a slow pool, with a removal rate that was dependent on the initial chi(C) but that did not vary as chi(C) decreased during the course of one experiment. The cholesterol activity therefore seems to be affected by sample history as well as local concentration, which could be explained in terms of the formation of superlattices that are stable for relatively long times. We also describe a variation on the traditional lattice models, with phosphatidylcholine (PC) being treated as an arrangement of hexagonal tiles; the cholesterol is then introduced at any vertex point, without increasing the total area occupied by all the lipid molecules. This model is consistent with Langmuir trough measurements of total lipid area and provides a simple explanation for the maximum solubility of cholesterol in the PC bilayer.
Autor*innen der BOKU Wien:
Melzak Kathryn
Toca-Herrera José Luis
BOKU Gendermonitor:


Find related publications in this database (Keywords)
cholesterol
cyclodextrin
liposome
membrane
membrane lateral organisation
OPPC
POPC
solubility
superlattice
surface plasmon resonance


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