Temperature-induced micelle to vesicle transition: kinetic effects in the DMPC/NaC system

Lesieur, P.; Киселев, М. А.; Barsukov, L.I.; Lombardo, Domenico

doi:10.1107/s0021889899012765

Cited by 55 publications

(55 citation statements)

References 18 publications

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“…The model of infinitely thin sphere was applied to interpret the SAXS curves in the region of scattering vector q from 0.005Å -1 to 0.04Å -1 [5]. The macroscopic cross section of vesicles in this model is given by…”

Section: Methodsmentioning

confidence: 99%

“…In our previous study, the 40% sucrose solution was used for the investigation of micelle to vesicle transition in the mixed DMPC/ionic surfactant system via SAXS [5]. In the present study, the possibility to use sucrose solutions as medium for X-ray and neutron small-angle scattering experiment was explored for DMPC vesicles and mixed DMPC/nonionic surfactant aggregates.…”

Section: Introductionmentioning

confidence: 99%

“…The radius of large unilamellar vesicles (R≥1000 Å) at itself cannot be determined from SANS or SAXS scattering experiment due to the technical limitation of modern spectrometers and large polydispersity of vesicles in size and morphology [9][10][11]. The methods to create small unilamellar vesicles (SUVs) with low polydispersity such as fast dilution or temperature jump protocol were developed for mixed lipid/surfactant systems [5,12]. The problem of creation of the SUVs with low polydispersity from a pure lipid system without surfactant are not solved till now.…”

Section: Introductionmentioning

confidence: 99%

“…The small-angle X-ray (SAXS) and neutron (SANS) scattering experiment on vesicles from phospholipids serving as a model biological membranes is a useful method for determination of membrane and vesicle structure [4][5][6][7][8][9]. The Guinier approximation of SANS spectra was used for the calculation of membrane thickness of egg yolk phosphatidylcholine vesicles (d l =41.7Å at 20 o C), dipalmitoylphosphatidylcholine (DPPC) vesicles (d l =49.6Å at 20 o C), and mixed lipid/surfactant vesicles [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Sucrose solutions as prospective medium to study the vesicle structure: SAXS and SANS study

Киселев

Lesieur²,

Kisselev

et al. 2001

Journal of Alloys and Compounds

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The possibility to use sucrose solutions as medium for X-ray and neutron small-angle scattering experiments has been explored for dimyristoylphosphatidylcholine (DMPC) vesicles and mixed DMPC/C 12 E 8 aggregates. The influence of sucrose concentration on phospholipid vesicles size and polydispersity has been investigated by complimentary X-ray and neutron scattering. Sucrose solutions decreased vesicle size and polydispersity and increased a contrast between phospholipid membrane and bulk solvent sufficiently for X-rays. 40% sucrose in H 2 O increased X-ray contrast by up to 10 times compared to pure H 2 O. The range of sucrose concentration 30%-40% created the best experimental conditions for the X-ray small-angle experiment with phospholipid vesicles.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sucrose solutions as prospective medium to study the vesicle structure: SAXS and SANS study

Киселев

Lesieur²,

Kisselev

et al. 2001

Journal of Alloys and Compounds

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“…The transformation is driven by a very large difference in spontaneous curvatures between phospholipid and amphiphile which is dependent on the amphiphile/phospholipid molar ratio. Decreasing the amphiphile concentration-by the dissolution of mixed micelles [37][38][39] or by the reduction of partitioning of the amphiphile into a lipid 7 phase by changing the temperature [40][41][42][43][44]-results in a transformation into bilayer vesicles.…”

Section: Resultsmentioning

confidence: 99%

Synchrotron SAX and WAX diffraction study of a hydrated very long-chain, dendritic amphiphile+DPPC mixture

Karlovská

Williams

Macri

et al. 2007

Colloids and Surfaces B: Biointerfaces

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The tri-headed anionic dendritic amphiphile, 4-(2-carboxyethyl)-4-[(icosyloxycarbonyl)amino]heptanedioic acid (3CCb20), forms solid-like gel-state mixed micelles with dipalmitoylphosphatidylcholine (DPPC) in excess water at 3CCb20 : DPPC = 0.91 : 1 molar ratio. On heating, these micelles transform into fluid bilayers stacked in the liquid crystalline lamellar L α phase at about 40 °C. This phase transition and the microstructure of 3CCb20 + DPPC aggregates were studied using smalland wide-angle synchrotron X-ray diffraction. The ability of 3CCb20 to solubilize solid-like lipid bilayers could be important in microbiocidal activities of 3CCb20, including in its anti-HIV activity.Keywords: amphiphiles; DPPC; micelles; bilayers; X-ray diffraction; phase transition 3 IntroductionSaturated fatty acids have a long history as microbicides against many pathogens [1][2][3][4][5]. Measurements of inhibitory activities can be problematic because of the very low solubility of saturated fatty acids in aqueous solutions [6]. Furthermore, as the chain length increases to C 18 and beyond, the aqueous solubility becomes immeasurable. Knowing that the compounds completely dissolve in aqueous media enables speculation about how chain length affects microbiological activity. In a homologous series of compounds, antimicrobial activity can show a cut-off effect [7]. Without knowing that the amphiphiles fully dissolve in aqueous media, we cannot conclude that the cut-off effect is due to the "intrinsic" activity of the amphiphiles or due to the decreased solubility of the amphiphile in the microbiological media. The antimicrobial data for 3CCbn show that longer chains (3CCb18-22) are more active than the shorter chains (3CCb14-16). These data contrast with those of saturated fatty acids, where the most active compounds are in the range of C 8 to C 14 [1][2][3][4][5]. A dendritic structure should reduce the absorption of an amphiphile into a cell. The highly branched structure of the head group resembles the dendritic structure of glycolipids that are anchored on the outside of cells. Branching and the triple charge might retard diffusion across membranes. Given the success of very long chain amphiphiles as antimicrobials, there might be a preference for absorption of these amphiphiles on pathogens as opposed to epithelial cells resulting in the reduced irritancy.To understand molecular mechanisms in the biological activities of these compounds, their interactions with different cell constituents must be studied. Several researchers [2,5,19] have proposed that the microbicidal mechanism of action involves fatty acids interacting with membranes. Because of the long alkyl chains, 3CCbn will likely partition into biological membranes. Upon doing so, these amphiphiles will affect the structure and dynamics of the membrane. The phospholipid bilayer comprises the structural matrix of biological membranes. Understanding how amphiphiles interact with a phopholipid bilayer will provide clues to the molecular mechanism of the biological a...

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Molekülverbände von Perylenbisimid‐Farbstoffen in Wasser

2012

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Perylenbisimide zählen zu den bedeutendsten funktionellen Farbstoffen mit vielfältigen Anwendungsmöglichkeiten. Aufgrund ihrer chemischen Robustheit, Photostabilität und herausragenden optischen und elektronischen Eigenschaften wurden sie als Pigmentfarbstoffe, Fluoreszenzsonden sowie n‐Halbleiter in der organischen Elektronik und Photovoltaik eingesetzt. Das ausgedehnte quadrupolare π‐System dieser Farbstoffklasse ermöglichte außerdem die Herstellung zahlreicher supramolekularer Architekturen mit faszinierenden photophysikalischen Eigenschaften. Jedoch blieb der supramolekulare Ansatz zur Bildung von Perylenbisimid‐Molekülverbänden größtenteils organischen Medien vorbehalten. Erfreulicherweise gab es in den letzten Jahren beachtliche Bemühungen zur Entwicklung von wasserlöslichen Perylenbisimiden und deren Anwendungen in wässrigen Medien. Dieser Aufsatz gibt einen aktuellen Überblick über die Selbstorganisation von Perylenbisimiden durch π‐π‐Wechselwirkung im wässrigen Medium. Synthetische Strategien zur Herstellung von wasserlöslichen Perylenbisimiden und der Einfluss des Wassers auf die π‐π‐Stapelung von Perylenbisimiden, sowie daraus resultierende Anwendungen werden eingehend diskutiert.

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Temperature-induced micelle to vesicle transition: kinetic effects in the DMPC/NaC system

Cited by 55 publications

References 18 publications

Sucrose solutions as prospective medium to study the vesicle structure: SAXS and SANS study

Sucrose solutions as prospective medium to study the vesicle structure: SAXS and SANS study

Synchrotron SAX and WAX diffraction study of a hydrated very long-chain, dendritic amphiphile+DPPC mixture

Molekülverbände von Perylenbisimid‐Farbstoffen in Wasser

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