Ordered micellar and inverse micellar lyotropic phases

Shearman, Gemma C.; Tyler, Arwen I. I.; Brooks, Nicholas J.; Templer, Richard H.; Ces, Oscar; Law, Robert V.; Seddon, John M.

doi:10.1080/02678292.2010.484917

Cited by 53 publications

(65 citation statements)

References 109 publications

(148 reference statements)

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“…We inferred that the LC here should be of an I 2 phase, i.e., reverse micellar cubic liquid crystalline. 20,21 Bragg reections of 1 : 1.160 : 1.651 : 1.923 : 1.996 : 2.306 : 2.563 were obtained, which agreed with the characteristic ratios of O3 : O4 : O8 : O11 : O12 : O16 : O19 : . (or 1 : 1.155 : 1.633 : 1.915 : 2 : 2.309 : 2.517 : .)…”

Section: Aggregating Structuressupporting

confidence: 80%

Self-assembly of quaternary ammonium gemini surfactants in cyclohexane upon reinforcement by simple counterions

2018

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Section: Aggregating Structuressupporting

confidence: 80%

Self-assembly of quaternary ammonium gemini surfactants in cyclohexane upon reinforcement by simple counterions

2018

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“…[36][37][38] A lamellar to cubic phase transition may be induced in membranes by temperature or pressure jumps in systems containing lipids with negative curvature. 39,40 Alternatively, inverse phases can be induced by the addition of a largely hydrophobic co-surfactant.…”

Section: The Suppression Of Cubic Phases By Cholesterolmentioning

confidence: 99%

Cholesterol expels ibuprofen from the hydrophobic membrane core and stabilizes lamellar phases in lipid membranes containing ibuprofen

et al. 2015

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There is increasing evidence that common drugs, such as aspirin and ibuprofen, interact with lipid membranes. Ibuprofen is one of the most common over the counter drugs in the world, and is used for relief of pain and fever. It interacts with the cyclooxygenase pathway leading to inhibition of prostaglandin synthesis. From X-ray diffraction of highly oriented model membranes containing between 0 and 20 mol% ibuprofen, 20 mol% cholesterol, and dimyristoylphosphatidylcholine (DMPC), we present evidence for a non-specific interaction between ibuprofen and cholesterol in lipid bilayers. At a low ibuprofen concentrations of 2 mol%, three different populations of ibuprofen molecules were found: two in the lipid head group region and one in the hydrophobic membrane core. At higher ibuprofen concentrations of 10 and 20 mol%, the lamellar bilayer structure is disrupted and a lamellar to cubic phase transition was observed. In the presence of 20 mol% cholesterol, ibuprofen (at 5 mol%) was found to be expelled from the membrane core and reside solely in the head group region of the bilayers. 20 mol% cholesterol was found to stabilize lamellar membrane structure and the formation of a cubic phase at 10 and 20 mol% ibuprofen was suppressed. The results demonstrate that ibuprofen interacts with lipid membranes and that the interaction is strongly dependent on the presence of cholesterol.

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“…These branched inverse micellar phases are now part of the standard phase diagram of lipid self-assembly. 10,61,89,90 In this article, we analyse hypothetical polycontinuous geometries as candidate structures for lipid self-assembly under the following assumptions: the self-assembled system consists of three or four identical network-like aqueous domains, termed K, centred on periodic intertwined (or interthreaded) networks. The aqueous domains are bound by surfaces, S, of a constant mean curvature (CMC) with the same topology and symmetry as the underlying network; h 0 denotes the value of the mean curvature.…”

Section: 51-56mentioning

confidence: 99%

Polycontinuous geometries for inverse lipid phases with more than two aqueous network domains

et al. 2013

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Inverse bicontinuous cubic phases with two aqueous network domains separated by a smooth bilayer are firmly established as equilibrium phases in lipid/water systems. The purpose of this article is to highlight the generalisations of these bicontinuous geometries to polycontinuous geometries, which could be realised as lipid mesophases with three or more network-like aqueous domains separated by a branched bilayer. An analysis of structural homogeneity in terms of bilayer width variations reveals that ordered polycontinuous geometries are likely candidates for lipid mesophase structures, with similar chain packing characteristics to the inverse micellar phases (that once were believed not to exist due to high packing frustration). The average molecular shape required by global geometry to form these multi-network phases is quantified by the surfactant shape parameter, v/(al); we find that it adopts values close to those of the known lipid phases. We specifically analyse the 3etc(187 193) structure of hexagonal symmetry P6 3 /mcm with three aqueous domains, the 3dia(24 220) structure of cubic symmetry I 43d composed of three distorted diamond networks, the cubic chiral 4srs(24 208) with cubic symmetry P4 2 32 and the achiral 4srs(5 133) structure of symmetry P4 2 /nbc, each consisting of four intergrown undistorted copies of the srs net (the same net as in the Q G II gyroid phase). Structural homogeneity is analysed by a medial surface approach assuming that the headgroup interfaces are constant mean curvature surfaces. To facilitate future experimental identification, we provide simulated SAXS scattering patterns that, for the 4srs(24 208) and 3dia(24 220) structures, bear remarkable similarity to those of bicontinuous Q G II -gyroid and Q D II -diamond phases, with comparable lattice parameters and only a single peak that cannot be indexed to the wellestablished structures. While polycontinuous lipid phases have, to date, not been reported, the likelihood of their formation is further indicated by the reported observation of a solid tricontinuous mesoporous silicate structure, termed IBN-9, which formed in the presence of surfactants [Han et al

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Ordered micellar and inverse micellar lyotropic phases

Cited by 53 publications

References 109 publications

Self-assembly of quaternary ammonium gemini surfactants in cyclohexane upon reinforcement by simple counterions

Self-assembly of quaternary ammonium gemini surfactants in cyclohexane upon reinforcement by simple counterions

Cholesterol expels ibuprofen from the hydrophobic membrane core and stabilizes lamellar phases in lipid membranes containing ibuprofen

Polycontinuous geometries for inverse lipid phases with more than two aqueous network domains

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