Journal ArticleDOI
Mechanical properties of lipid bilayers: a note on the Poisson ratio.
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TLDR
It is concluded that lipid membrane deformations are to a very good approximation volume-preserving, with a Poisson ratio that is likely about 3% smaller than the common soft matter limit.Abstract:
We investigate the Poisson ratio ν of fluid lipid bilayers, i.e., the question how area strains compare to the changes in membrane thickness (or, equivalently, volume) that accompany them. We first examine existing experimental results on the area- and volume compressibility of lipid membranes. Analyzing them within the framework of linear elasticity theory for homogeneous thin fluid sheets leads us to conclude that lipid membrane deformations are to a very good approximation volume-preserving, with a Poisson ratio that is likely about 3% smaller than the common soft matter limit . These results are fully consistent with atomistic simulations of a DOPC membrane at varying amount of applied lateral stress, for which we instead deduce ν by directly comparing area- and volume strains. To assess the problematic assumption of transverse homogeneity, we also define a depth-resolved Poisson ratio ν(z) and determine it through a refined analysis of the same set of simulations. We find that throughout the membrane's thickness, ν(z) is close to the value derived assuming homogeneity, with only minor variations of borderline statistical significance.read more
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Scaling relationships for the elastic moduli and viscosity of mixed lipid membranes
Elizabeth G. Kelley,Paul Butler,Rana Ashkar,Robert Bradbury,Robert Bradbury,Michihiro Nagao,Michihiro Nagao,Michihiro Nagao +7 more
TL;DR: The results show that the membrane properties can be manipulated through lipid composition the same way bimodal blends of surfactants, liquid crystals, and polymers are used to engineer the mechanical properties of soft materials, with broad implications for understanding how lipid diversity relates to biomembrane function.
Journal ArticleDOI
Mechanics of Bacterial Interaction and Death on Nanopatterned Surfaces
TL;DR: A robust computational analysis of bacteria-nanopattern interaction is performed using three-dimensional finite element modelling which incorporates relevant continuum mechanical properties, multilayered envelope structure and adhesion interaction conditions, and demonstrates that envelope deformation is increased by adhesion to nanopatterns with smaller pillar radii and spacing.
Journal ArticleDOI
Determining the Gaussian Curvature Modulus of Lipid Membranes in Simulations: A Comparative Study via Global Shape Transformations and Local Stress Distributions
TL;DR: In this paper, the Gaussian curvature modulus κ-bar was determined in silico by monitoring patch-closure processes of pre-curved circular bilayers, and the elastic ratios between the two curvatures were found to be in the range between −085 and −105.
Journal ArticleDOI
Imaging non-classical mechanical responses of lipid membranes using molecular rotors
Miguel Paez-Perez,Ismael López-Duarte,Ismael López-Duarte,Aurimas Vyšniauskas,Nicholas J. Brooks,Marina K. Kuimova +5 more
TL;DR: The results suggest that the relationship between membrane tension and microviscosity is strongly influenced by the bilayer's lipid composition, and it is shown that the effects of increasing tension are minimised for membranes that exhibit liquid disordered – liquid ordered phase coexistence; while, surprisingly, membranes in pure gel and Lo phases exhibit a negative compressibility behaviour.
Journal ArticleDOI
Additional contributions to elastic energy of lipid membranes: Tilt-curvature coupling and curvature gradient
TL;DR: A stable elastic energy functional is derived, showing that the squared gradient of the curvature was missed in both of these works, and this change in the energy functional arises from a more accurate consideration of the transverse shear deformation terms and their influence on the membrane stability.
References
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Journal ArticleDOI
The MARTINI force field : Coarse grained model for biomolecular simulations
TL;DR: An improved and extended version of the coarse grained lipid model is presented, coined the MARTINI force field, based on the reproduction of partitioning free energies between polar and apolar phases of a large number of chemical compounds to reproduce the free energies of these chemical building blocks.
Book
Molecular theory of capillarity
John S. Rowlinson,B. Widom +1 more
TL;DR: The theory of Van Der Waals statistical mechanics of the liquid-gas surface model fluids in the mean-field approximation computer simulation of the calculation of the density profile three-phase equilibrium interfaces near critical points as mentioned in this paper.
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Structure of lipid bilayers
TL;DR: The uncertainty in structural results for lipid bilayers is being reduced and best current values are provided for bilayers of five lipids.
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Effect of Chain Length and Unsaturation on Elasticity of Lipid Bilayers
TL;DR: To test this hypothesis, peak-to-peak headgroup thicknesses h(pp) of bilayers were obtained from x-ray diffraction of multibilayer arrays at controlled relative humidities and showed that poly-cis unsaturated chain bilayers are thinner and more flexible than saturated/monounsaturated chain Bilayers.
Journal ArticleDOI
Perspective on the Martini model.
TL;DR: The Martini model, a coarse-grained force field for biomolecular simulations, has found a broad range of applications since its release a decade ago and is described as a building block principle model that combines speed and versatility while maintaining chemical specificity.