Dataset Information

Composition Dependence of Water Permeation Across Multicomponent Gel-Phase Bilayers.

ABSTRACT: The permeability of multicomponent phospholipid bilayers in the gel phase is investigated via molecular dynamics simulation. The physical role of the different molecules is probed by comparing multiple mixed-component bilayers containing distearylphosphatidylcholine (DSPC) with varying amounts of either the emollient isostearyl isostearate or long-chain alcohol (dodecanol, octadecanol, or tetracosanol) molecules. Permeability is found to depend on both the tail packing density and hydrogen bonding between lipid headgroups and water. Whereas the addition of emollient or alcohol molecules to a gel-phase DSPC bilayer can increase the tail packing density, it also disturbed the hydrogen-bonding network, which in turn can increase interfacial water dynamics. These phenomena have opposing effects on bilayer permeability, which is found to depend on the balance between enhanced tail packing and decreased hydrogen bonding.

SUBMITTER: Hartkamp R

PROVIDER: S-EPMC6028149 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Composition Dependence of Water Permeation Across Multicomponent Gel-Phase Bilayers.

Hartkamp Remco R Moore Timothy C TC Iacovella Christopher R CR Thompson Michael A MA Bulsara Pallav A PA Moore David J DJ McCabe Clare C

The journal of physical chemistry. B 20180320 12

The permeability of multicomponent phospholipid bilayers in the gel phase is investigated via molecular dynamics simulation. The physical role of the different molecules is probed by comparing multiple mixed-component bilayers containing distearylphosphatidylcholine (DSPC) with varying amounts of either the emollient isostearyl isostearate or long-chain alcohol (dodecanol, octadecanol, or tetracosanol) molecules. Permeability is found to depend on both the tail packing density and hydrogen bondi ...[more]

PMID: 29504755

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Project description:We have studied an expansion behavior of pressurized bubbles at the orifice of a capillary inserted in gelator-solvent (agarose-water) mixtures as a function of the gelator concentration in which the phase transition points are included. The pressure (P) -dependence of the radius of the curvature (R) of the bubbles monitored by laser beam has shown a discontinuous decrease in the exponent (m) of the experimental power law R = KΔP-m (K: constant) from 1 to 1/2 and a discontinuous increase in the average surface tension (γave) obtained from the work-area plots of the mixtures exceeding that of pure water (72.6 mN/m) at 0.02 < [agarose] < 0.03 wt%, which is attributed to the disappearance of the fluidity. The apparent surface tension (γapp = ΔP/2 R) of the system in the concentration range of 0.03-0.20 wt% has been analyzed by a modified Shuttleworth equation γapp = σ0 + τln(A/A0), where σ0 is an isotropic constant component and the second term is a surface area (A) -dependent elastic component, in which τ is the coefficient and A0 is the area of the orifice. The analysis has indicated that σ0 coincides with the γapp value of the mixture of 0.02 wt% and the second term at >0.02 wt% is the dominant component. From the appearance of the elastic component and concentration dependence of τ, the plateau of τ for the agarose-water mixtures at 0.03-0.10 wt% (Region II) has been explained to the phase separation giving two-phase mixtures of 0.02 wt% sol and 0.10 wt% gel and the upward inflection of τ at 0.10 wt% has been assigned to an increase in the elasticity of the gel with the increase of the agarose concentration in the range of >0.10 wt% (Region III). On considering the concentration dependence of the surface tension of agarose-water mixtures, the discontinuous and inflection points were assigned to the 1st- and 2nd-order phase transition concentrations of the agarose gel, respectively. Given the results with our tensiometry based on the optical bubble pressure method, distinct gelation points for other systems could be determined both mechanically and thermodynamically which will provide a diagnostic criterion of sol-gel transitions.

Dataset Information

Composition Dependence of Water Permeation Across Multicomponent Gel-Phase Bilayers.

Publications

Composition Dependence of Water Permeation Across Multicomponent Gel-Phase Bilayers.

Similar Datasets

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