Monitoring the Nucleation of Crystalline Films of Cholesterol on Water and in the Presence of Phospholipid

Lafont, Sylvaine; Rapaport, Hanna; Sömjen, Giora J.; Renault, Anne; Howes, P.B.; Kjær, Kristian; Als‐Nielsen, J.; Leiserowitz, Leslie; Lahav, Meir

doi:10.1021/jp973074e

Cited by 70 publications

(104 citation statements)

References 17 publications

(26 reference statements)

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“…2, we found that the refractive index of cholesterol monohydrate along the c axis, which is perpendicular to both the plate shaped crystal and the ribbon surface, is n ϭ 1.522 Ϯ 0.003. Interestingly, this value falls into the range 1.49 Ϯ 0.06, which was measured by ellipsometry for a cholesterol monolayer on air-water interface (24).…”

Section: Methodsmentioning

confidence: 70%

Thickness–radius relationship and spring constants of cholesterol helical ribbons

Khaykovich

Kozlova

Choi

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Using quantitative phase microscopy, we have discovered a quadratic relationship between the radius R and the thickness t of helical ribbons that form spontaneously in multicomponent cholesterol-surfactant mixtures. These helical ribbons may serve as mesoscopic springs to measure or to exert forces on nanoscale biological objects. The spring constants of these helices depend on their submicroscopic thickness. The quadratic relationship (R ؔ t 2 ) between radius and thickness is a consequence of the crystal structure of the ribbons and enables a determination of the spring constant of any of our helices solely in terms of its observable geometrical dimensions.biological force spectroscopy ͉ elasticity of thin films ͉ phase-contrast microscopy in biophysics T he elastic properties of meso-and nanoscale thin elastic strips forming helical ribbons or tubules, have been the focus of active recent research in both biophysics and nanoscience communities (1-7). We have discovered that in a number of complex aqueous solutions containing a sterol (cholesterol in particular) and a mixture of surfactants, the sterol molecules may self-assemble into ribbons of helical shape (8). The geometry of the helical ribbons is characterized by the radius, width, thickness, contour length, and pitch angle, see figure 1a in ref. 9. Remarkably, the pitch angle is always either 11°or 54°, whereas axial length, width, and radius vary by two orders of magnitude in the range from 1 to Ϸ100 m. These helical ribbons are fascinating objects for fundamental studies (2,(8)(9)(10). Furthermore, because low-pitch helical ribbons have spring constants in the range of 0.5 to 500 pN/m (2), and the elongation of these springs from 1 m up to 100 m can easily be observed microscopically, it follows that they can be used as mesoscopic spring scales to measure forces between nanoscale biological objects in the range from 0.5 pN to 50 nN. For this and other applications, the ability to readily determine the spring constants of individual helixes is of crucial importance. In this article, we establish the relationship between the spring constant of the low-pitch cholesterol helical ribbons and its readily observable dimensions: width, radius, and length.Originally, it had been thought that cholesterol helical ribbons formed in surfactant mixtures had liquid crystalline structure and that their shape was governed by elastic properties of liquid crystalline layer (9,11,12). Recently, we have shown by X-ray diffraction that these helical ribbons are, in fact, single crystals with structure closely resembling that of cholesterol monohydrate (10). Having in mind the single-crystal nature of our ribbons, we have proposed that their helical shape is determined by a balance between two terms in the free energy of deformation of the cholesterol crystalline strip (2). The first term, the spontaneous bending energy, favors curling toward one of the two faces of the ribbon and is linear in curvature, ϪK s /R. The second term is the elastic energy of bending a strip. Thi...

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Section: Methodsmentioning

confidence: 70%

Thickness–radius relationship and spring constants of cholesterol helical ribbons

Khaykovich

Kozlova

Choi

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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“…The structure of compressed cholesterol monolayers at the air ± water interface was recently determined by using grazing incidence X-ray diffraction (GID). [17] Cholesterol forms crystalline domains of coherence length of 100 , with the steroid backbone tilted approximately 158 relative to the vertical. According to the measured area per molecule of epicholesterol, the molecule is presumably even less tilted.…”

Section: Discussionmentioning

confidence: 99%

“…Cholesterol monolayers at the air ± water interface were recently shown to be composed of two-dimensional crystallites with a coherence length of 100 . [17] At the boundaries of these domains, three-dimensional structural features similar to those of the crystalline lattice may be reproduced. The antibodies raised against cholesterol monohydrate crystals do indeed interact with monolayers of cholesterol at the air ± water interface.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Interactions of a Specialized Antibody with Cholesterol and Epicholesterol Monolayers

Izhaky

Addadi

2000

Chem. Eur. J.

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The stereoselective recognition by monoclonal antibodies of two-dimensional monolayers of cholesterol spread at the air-water interface is presented. Using immunofluorescence, we show that one antibody, raised and selected against crystals of cholesterol monohydrate, specifically recognizes monolayers of cholesterol, but not monolayers of epicholesterol--its epimeric form. This demonstrates that stereoselective recognition also applies to protein-surface interactions.

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“…Hence, the formation of a stable Langmuir monolayer is important for the formation of controlled and organized LB films. It is well known that the Ch molecules form a stable monolayer at the A-W interface Slotte & Mattjus (1995); Lafont et al (1998). Though -SH group is weakly acidic in nature Bilewicz & Majda (1991), the amphiphilic balance of the TCh for the formation of a There are numerous reports in literature indicating the formation of mixed monolayer of a non-amphiphilic component doped into the monolayer of amphiphilic molecules (Silva et al, 1996;Wang et al, 2000;Viswanath & Suresh, 2004).…”

Section: Molecular Interaction At Air-water Interfacementioning

confidence: 99%

Molecular Interactions at Interfaces

Gupta¹,

Manjuladevi²

2012

Molecular Interactions

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gold nanoparticle (AGN) exhibited variety of surface phases like low ordered liquid phase, high ordered liquid phase, bilayer of high ordered liquid phase and a collapsed state. Based on the thermodynamical studies of Langmuir monolayer of AGN, a phase diagram has been constructed. The Langmuir films at A-W interface can be transferred to solid substrates by LB technique. Here also, the nature of aggregation and deposition depends on molecule-substrates and intermolecular interaction. Interestingly, it was found that repeated process of adsorption and partial desorption of cholesterol molecules from hydrophobic substrates lead to the formation of uniformly distributed torus shaped domains.

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Monitoring the Nucleation of Crystalline Films of Cholesterol on Water and in the Presence of Phospholipid

Cited by 70 publications

References 17 publications

Thickness–radius relationship and spring constants of cholesterol helical ribbons

Thickness–radius relationship and spring constants of cholesterol helical ribbons

Stereoselective Interactions of a Specialized Antibody with Cholesterol and Epicholesterol Monolayers

Molecular Interactions at Interfaces

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