Structural requirements of sterols for myelin tube formation with sodium oleate

Neuzil, E; Fourche, J.; Jensen, Robert G.; Jensen, H.; Morin, Gregg B.

doi:10.1016/0005-2736(81)90565-4

Cited by 9 publications

(6 citation statements)

References 12 publications

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“…For instance, instead of contacting the L α phase with water, one can also bring the pure surfactant in contact with water. Myelins were also observed in mixtures containing cholesterol and aqueous ionic surfactant solutions, or oil, nonionic surfactants, and water. , Also in these latter cases, the myelins are based on the lyotropic L α phase.…”

Section: Introductionmentioning

confidence: 99%

Myelin Structures Formed by Thermotropic Smectic Liquid Crystals

et al. 2013

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We report on transient structures, formed by thermotropic smectic-A liquid crystals, resembling the myelin figures of lyotropic lamellar liquid crystals. The thermotropic myelin structures form during the solubilization of a smectic-A droplet in an aqueous phase containing a cationic surfactant at concentrations above the critical micelle concentration. Similar to the lyotropic myelin figures, the thermotropic myelins appear in an optical microscope as flexible tubelike structures growing at the smectic/aqueous interface. Polarizing microscopy and confocal fluorescence microscopy show that the smectic layers are parallel to the tube surface and form a cylindrically bent arrangement around a central line defect in the tube. We study the growth behavior of this new type of myelins and discuss similarities to and differences from the classical lyotropic myelin figures.

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Section: Introductionmentioning

confidence: 99%

Myelin Structures Formed by Thermotropic Smectic Liquid Crystals

et al. 2013

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“…These interface instabilities can form during the dissolution and swelling of surfactant lamellar phases. Despite an increasing interest in these structures, − there is currently no accepted explanation for the formation of myelins.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Structure and Growth of Myelins

et al. 2010

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After contact with water, surfactant lamellar phases (L R ) can show spectacular interface instabilities: multibilayer tubules, so-called myelins, grow from the L R /water interface into the water. We have studied the shape, size, and growth of myelins in aqueous solutions of the nonionic surfactant C 12 E 3 (triethylene glycol monododecyl ether) during dissolution. We used a combination of different imaging techniques: optical microscopy providing 2-D projections of the sample and confocal microscopy offering a complete 3-D reconstruction. These techniques provide quantitative information on the shape and growth of myelins, such as their width, length, and depth profile as a function of time. The growth rate of myelins, characterized by a swelling or diffusion coefficient, was found to increase with surfactant mass fraction and, seemingly, with sample thickness. We demonstrate that myelin creaming due to buoyancy can explain the apparent dependence on sample thickness. Our experiments furthermore suggest that myelin growth is controlled by an interplay between the water mobility in the lamellar phase and the osmotic pressure difference between the lamellar phase and the contacting water.

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“…Concerning to organic amphiphiles, molecular tubes are obtained by chiral molecular self-assembly (the importance of chirality in the formation of superstructures was recognized by Furhop et al), generally requiring highly ordered molecular packing and anisotropic intermolecular interactions. This is the case for fatty acid salts, phospholipids, − diacetylenic lipids, glycolipids, − peptidic amphiphiles, − sterols, − bile salts, − and cholesterol (which evidence a prominent position). − ,, In fact, metastable helical and tubular intermediates have been observed in the pathway for cholesterol crystallization in native and model biles …”

Section: Introductionmentioning

confidence: 99%

Supramolecular Structures Generated by a p-tert-Butylphenylamide Derivative of Deoxycholic Acid. From Planar Sheets to Tubular Structures through Helical Ribbons

et al. 2010

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The formation of supramolecular structures initiated by a p-tert-butylphenylamide derivative of deoxycholic acid (Na-t-butPhDC) is investigated. At 1.18 mM concentration of Na-t-butPhDC and 37 degrees C, initial flat ribbons are observed which self-transform into helical ribbons (with a mean pitch angle of 47 +/- 6 degrees) which finally originate molecular tubes with an external diameter of 241 +/- 28 nm. Most of the molecular tubes show helical markings with a pitch angle value of 45 +/- 4 degrees, in full agreement with predictions of simple models based on chiral elastic properties of the membrane. A lateral association mechanism is proposed to account for the growth of the external diameter (from 225 +/- 32 to 546 +/- 59 nm) of tubes with time at 3.99 mM.

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Structural requirements of sterols for myelin tube formation with sodium oleate

Cited by 9 publications

References 12 publications

Myelin Structures Formed by Thermotropic Smectic Liquid Crystals

Myelin Structures Formed by Thermotropic Smectic Liquid Crystals

Three-Dimensional Structure and Growth of Myelins

Supramolecular Structures Generated by a p-tert-Butylphenylamide Derivative of Deoxycholic Acid. From Planar Sheets to Tubular Structures through Helical Ribbons

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