Cubic Phases of Lipid-containing Systems

Luzzati, Vittorio; Vargas, Rodolfo; Mariani, Paolo; Gulik, Annette; Delacroix, Hervé

doi:10.1006/jmbi.1993.1053

Cited by 184 publications

(112 citation statements)

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“…The evaluation of the x-ray spectra was achieved according to procedures described (39) and in previous papers (37,40,41) which allow us to assign the spacing ratios of the main scattering maxima to defined three-dimensional structures. Here, in particular lamellar (L) and nonlamellar inverted cubic (Q) structures are of relevance.…”

Section: Methodsmentioning

confidence: 99%

Non-lamellar Structure and Negative Charges of Lipopolysaccharides Required for Efficient Folding of Outer Membrane Protein PhoE of Escherichia coli

Cock

Brandenburg

Wiese

et al. 1999

Journal of Biological Chemistry

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Lipopolysaccharides (LPS) are amphiphilic molecules in the outer leaflet of the bacterial outer membrane. Recently, an early role for LPS in the folding of outer membrane porin PhoE was demonstrated in vitro. In order to elucidate the molecular mechanism of LPSprotein interactions, folding of PhoE protein was studied with a large set of well characterized LPS chemotypes. We demonstrate that negative charges in the inner core region contribute to the high efficiency of folding of PhoE protein. In addition, the supramolecular structure of the LPS aggregate seems to be important. LPS with a lipid A part that prefers a lamellar or a direct micellar structure and a high state of order of its acyl chains is much less efficient to support folding as compared with LPS with lipid A that prefers a non-lamellar structure and a low acyl chain order. These in vitro data indicate that extensive interactions between the core and lipid A region of LPS with the protein are required to support protein folding. The LPS-PhoE binding might be promoted by the presence of hydroxy fatty acids in the lipid A moiety of LPS.

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Section: Methodsmentioning

confidence: 99%

Non-lamellar Structure and Negative Charges of Lipopolysaccharides Required for Efficient Folding of Outer Membrane Protein PhoE of Escherichia coli

Cock

Brandenburg

Wiese

et al. 1999

Journal of Biological Chemistry

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“…[32]. In contrast to the situation for (almost balanced) ternary amphiphilic systems, the structure of bicontinuous cubic phases is well-established for many binary amphiphilic systems [6][7][8].…”

Section: Geometry Of Bicontinuous Phasesmentioning

confidence: 99%

“…Note that Tab. IV now provides data for G for the first time, which in fact is the cubic bicontinuous phase most relevant for amphiphilic systems [6][7][8].…”

Section: B Generating Triply Periodic Structuresmentioning

confidence: 99%

“…Clearly any bicontinuous ordered phase has to have a three-dimensional Bravais-lattice. In experiments, cubic symmetry is observed in most cases [6][7][8]. The amphiphilic monolayers of bicontinuous cubic structures, which separate regions with water from regions with oil, are often modelled by triply periodic surfaces of constant mean curvature [9,10].…”

Section: Introductionmentioning

confidence: 99%

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Systematic approach to bicontinuous cubic phases in ternary amphiphilic systems

1999

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The Fourier approach and theories of space groups and color symmetries are used to systematically generate and compare bicontinuous cubic structures in the framework of a Ginzburg-Landau model for ternary amphiphilic systems. Both single and double structures are investigated; they correspond to systems with one or two monolayers in a unit cell, respectively. We show how and why single structures can be made to approach triply periodic minimal surfaces very closely, and give improved nodal approximations for G, D, I-WP and P surfaces. We demonstrate that the relative stability of the single structures can be calculated from the geometrical properties of their interfaces only. The single gyroid G turns out to be the most stable bicontinuous cubic phase since it has the smallest porosity. The representations are used to calculate distributions of the Gaussian curvature and 2 H-NMR bandshapes for C(P), C(D), S, C(Y) and F-RD surfaces.

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“…Three structure of cubosomes have been proposed by Luzzati et al 9) ; (i) Pn3m (D-surface) (Diamond surface), (ii) Ia3d (G-surface) (Gyroid surface), and (iii) Im3m (P-surface) (Primitive surface), in terms of nodal surfaces.…”

mentioning

confidence: 99%

Cubosomes: An Overview

Garg

Saraf

2007

Biological & Pharmaceutical Bulletin

236

151

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Surfactant and polymers are generally used in the controlled drug delivery systems. Surfactant and polymer systems form supra-assemblies, which are extensively exploited as active delivery vehicles. These systems include liquid crystalline aggregates (e.g., liposomes and cubosomes) or cross-linked gel networks (hydrogels) that load, stabilize, and eventually deliver active ingredients. The potential for utilizing a particular active with a vehicle depends on the physicochemical properties of both. To achieve therapeutic effects, it must be possible to load sufficient amounts of the active, which largely depends on the interaction of the vehicle and active. Further, the integrity of the active must be retained through all stages: preparation, storage, and use. The release rate of actives must be controlled to achieve optimal drug release profiles, while ease of preparation and vehicle stability must also be considered. An optimal delivery vehicle must successfully encompass all these properties.Cubosomes are bicontinuous cubic phase liquid crystals have many properties that make them appealing as a universal vehicle for drug delivery. Luzzati et al. 1) first documented its geometric model supplied later by Scriven.2) Which is in the past decade have been examined for drug delivery.3) The surfactant assembles into bilayers that are twisted into a three dimension, periodic, minimal surface forming tightly packed structure, like "honeycombed" with bicontinuous domains of water and lipid.Cubosome particles are first prepared by mechanical fragmentation of the cubic lipid-water phase in a three-phase region containing a liposomal dispersion and to differentiate from liposomes, these particles have been termed as cubosomes. [4][5][6][7][8] Its structure is different from liposomes because its structure can simultaneously accommodate water-soluble, lipid-soluble, and amphiphilic molecules.Three structure of cubosomes have been proposed by Luzzati et al. 9); (i) Pn3m (D-surface) (Diamond surface), (ii) Ia3d (G-surface) (Gyroid surface), and (iii) Im3m (P-surface) (Primitive surface), in terms of nodal surfaces.The structure generally maintains the efficacy; stability of actives such as vitamins 10) and proteins. 11) Cubosomes are thermodynamically stable; lasting indefinitely.12) Colloidal dispersions of cubosomes can be stabilized by the addition of polymers.13) They also possess the potential for controlled delivery of actives, where diffusion is governed by the tortuous diffusion of the active through the "regular" channel structure of the cubic phase.14) Cubosomes possess a sufficient average degree of molecular orientation order to characterize by structural symmetry, and often form in aqueous surfactant system at relatively high ampiphile concentrations.History Luzzati and Husson 15) and Luzzati et al. first recognized the existence of cubic phases in lipid-water system using X-ray scattering measurement. Fontell et al. 16) drew similar conclusions regarding cubic phase in ternary systems of ampiphiles, oils and ...

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Cubic Phases of Lipid-containing Systems

Cited by 184 publications

References 0 publications

Non-lamellar Structure and Negative Charges of Lipopolysaccharides Required for Efficient Folding of Outer Membrane Protein PhoE of Escherichia coli

Non-lamellar Structure and Negative Charges of Lipopolysaccharides Required for Efficient Folding of Outer Membrane Protein PhoE of Escherichia coli

Systematic approach to bicontinuous cubic phases in ternary amphiphilic systems

Cubosomes: An Overview

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