Molecular Dynamics Simulations of a Characteristic DPC Micelle in Water

Abel, Stéphane; Dupradeau, François‐Yves; Marchi, Massimo

doi:10.1021/ct3003207

Cited by 68 publications

(115 citation statements)

References 122 publications

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“…In the second approach, we compute the SASA of the SL part in the aggregate (i.e., the headgroup, the double bond, the alkyl chain, and COOH) by splitting the SL molecule into six parts namely, the external and internal glucose (SASA GLA (Table S5). These values were computed with the trjVoronoi program developed in our group (see ref 99 and references cited therein). This program uses a Voronoi−Delauney tessellation 103,104 algorithm to estimate the surface shared between the SL and water atoms (excluding hydrogen).…”

Section: The Journal Of Physical Chemistry Bmentioning

confidence: 99%

Structure of Bolaamphiphile Sophorolipid Micelles Characterized with SAXS, SANS, and MD Simulations

et al. 2015

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The micellar structure of sophorolipids, a glycolipid bolaamphiphile, is analyzed using a combination of small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS), and molecular dynamics (MD) simulations. Numerical modeling of SAXS curves shows that micellar morphology in the noncharged system (pH< 5) is made of prolate ellipsoids of revolution with core-shell morphology. Opposed to most surfactant systems, the hydrophilic shell has a nonhomogeneous distribution of matter: the shell thickness in the axial direction of the ellipsoid is found to be practically zero, while it measures about 12 Å at its cross-section, thus forming a "coffee bean"-like shape. The use of a contrast-matching SANS experiment shows that the hydrophobic component of sophorolipids is actually distributed in a narrow spheroidal region in the micellar core. These data seem to indicate a complex distribution of sophorolipids within the micelle, divided into at least three domains: a pure hydrophobic core, a hydrophilic shell, and a region of less defined composition in the axial direction of the ellipsoid. To account for these results, we make the hypothesis that sophorolipid molecules acquire various configurations within the micelle including bent and linear, crossing the micellar core. These results are confirmed by MD simulations which do show the presence of multiple sophorolipid configurations when passing from spherical to ellipsoidal aggregates. Finally, we also used Rb(+) and Sr(2+) counterions in combination with anomalous SAXS experiments to probe the distribution of the COO(-) group of sophorolipids upon small pH increase (5 < pH < 7), where repulsive intermicellar interactions become important. The poor ASAXS signal shows that the COO(-) groups are rather diffused in the broad hydrophilic shell rather than at the outer micellar/water interface.

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Section: The Journal Of Physical Chemistry Bmentioning

confidence: 99%

Structure of Bolaamphiphile Sophorolipid Micelles Characterized with SAXS, SANS, and MD Simulations

et al. 2015

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“…DPC micelles are relatively spherical bodies with a radius of approximately 18.6–23.3 Å, formed by 44–61 monomers per micelle 21. The length of the helix formed by LytA 239–252 in the presence of DPC micelles, which was measured from the N to C‐end distances in the calculated structures by using MOLMOL,22 is approximately 22 Å.…”

Section: Resultsmentioning

confidence: 99%

Uncatalyzed Hydroamination of Electrophilic Organometallic Alkynes: Fundamental, Theoretical, and Applied Aspects

Wang¹,

Latouche²,

Rapakousiou³

et al. 2014

Chemistry A European J

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Simple reactions of the most used functional groups allowing two molecular fragments to link under mild, sustainable conditions are among the crucial tools of molecular chemistry with multiple applications in materials science, nanomedicine, and organic synthesis as already exemplified by peptide synthesis and "click" chemistry. We are concerned with redox organometallic compounds that can potentially be used as biosensors and redox catalysts and report an uncatalyzed reaction between primary and secondary amines with organometallic electrophilic alkynes that is free of side products and fully "green". A strategy is first proposed to synthesize alkynyl organometallic precursors upon addition of electrophilic aromatic ligands of cationic complexes followed by endo hydride abstraction. Electrophilic alkynylated cyclopentadienyl or arene ligands of Fe, Ru, and Co complexes subsequently react with amines to yield trans-enamines that are conjugated with the organometallic group. The difference in reactivities of the various complexes is rationalized from the two-step reaction mechanism that was elucidated through DFT calculations. Applications are illustrated by the facile reaction of ethynylcobalticenium hexafluorophosphate with aminated silica nanoparticles. Spectroscopic, nonlinear-optical and electrochemical data, as well as DFT and TDDFT calculations, indicate a strong push-pull conjugation in these cobalticenium- and Fe- and Ru-arene-enamine complexes due to planarity or near-planarity between the organometallic and trans-enamine groups involving fulvalene iminium and cyclohexadienylidene iminium mesomeric forms.

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“…This method can provide a detailed insight into the surface structure at molecular level. Many papers concerning this topic have been published [14][15][16][17][34][35], and some results have revealed reasonable coincidence with their experimental counterparts [14].…”

Section: Introductionmentioning

confidence: 93%

Molecular structure of ionic surfactant solution surface and effects of counter-ion therein—a joint investigation by simulation and experiment

et al. 2015

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The main goal of the current paper is to investigate the surface structure of ionic surfactant solutions at molecular level and the influences of the counter-ion in this course. The used methods are molecular dynamics simulation and neutral impact collision ion scattering spectroscopy. The surfactants are sodium dodecyl sulfate and cesium dodecyl sulfate. With Material Studio (MS), the concentration-depth profiles of all the components in the surface layer have been simulated. With those profiles, the surface pictures of the ionic surfactant solutions are mapped out in angstrom scale and the orientation of surface active dodecyl sulfate ion at the surface dependent on its surface density is derived. Simultaneously, neutral impact collision ion scattering spectroscopy is employed to investigate the same systems experimentally. The results indicate that the surface structure is profoundly influenced by surface density of the surfactant and specificity of the counter-ion; however, the orientation of the dodecyl sulfate ion on the surface is only subjected to its surface density but hardly affected by the properties of its counter-ion. The comparison between those simulated and experimental results reveals reasonable agreements, indicating the reliability of this investigation as well as the reliability of the simulation strategy applied in these systems.

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Molecular Dynamics Simulations of a Characteristic DPC Micelle in Water

Cited by 68 publications

References 122 publications

Structure of Bolaamphiphile Sophorolipid Micelles Characterized with SAXS, SANS, and MD Simulations

Structure of Bolaamphiphile Sophorolipid Micelles Characterized with SAXS, SANS, and MD Simulations

Uncatalyzed Hydroamination of Electrophilic Organometallic Alkynes: Fundamental, Theoretical, and Applied Aspects

Molecular structure of ionic surfactant solution surface and effects of counter-ion therein—a joint investigation by simulation and experiment

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