Phospholipid Bilayers are Viscoelastic

Harland, Christopher W.; Bradley, Miranda; Parthasarathy, Raghuveer

doi:10.1016/j.bpj.2010.12.2954

Cited by 12 publications

(6 citation statements)

References 28 publications

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“…These low-frequency "floppy modes" are known from disordered colloidal crystals [52], colloidal glass formers, and supercooled liquids and signal the onset of macroscopic elasticity [53]. Phospholipid membranes also exhibit elasticity above and below the main phase transition [54] and the observed flow patterns [2] resemble very much dynamical heterogeneities [51], a hallmark of glassy dynamics, which were again suggested to be linked with the "floppy modes" [55].…”

Section: Phospholipid Motionsmentioning

confidence: 94%

The slow short-time motions of phospholipid molecules with a focus on the influence of multiple scattering and fitting artefacts

Büsch¹,

Unruh²

2011

J. Phys.: Condens. Matter

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Quasielastic neutron scattering is a powerful tool for the study of non-periodic motions in condensed matter as a detailed line shape analysis can give information about the geometry and rate of the scatterers' displacements. Unfortunately, there are also a number of artifacts which can masquerade as signatures of motions and can therefore lead to erroneous results. Their influence on the evaluation of the motions of the phospholipid dimyristoylphosphatidylcholine (DMPC) is discussed. On a 60 ps time scale, the long-range motion of the molecules has a flowlike character with similar velocities above and below the main phase transition. It is proposed that the concepts of dynamical heterogeneities and "floppy modes" developed in glass physics provide a framework to explain the observed behaviour.

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Section: Phospholipid Motionsmentioning

confidence: 94%

The slow short-time motions of phospholipid molecules with a focus on the influence of multiple scattering and fitting artefacts

Büsch¹,

Unruh²

2011

J. Phys.: Condens. Matter

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“…We assume that the surface viscous forces that develop on the membrane and determine its dynamics correspond to an area-preserving Newtonian surface fluid [4,26,27]. Our goal is thus to present a finite element method for the viscous flow of phospholipid bilayers; i.e., for the dynamical simulation of phospholipid bilayers, considering an elastic model for bending deformations and a (viscous) Newtonian area-preserving fluid model for the dissipative tangential motions.…”

Section: Introductionmentioning

confidence: 99%

A semi-implicit finite element method for viscous lipid membranes

Rodrigues

Ausas

Mut

et al. 2015

Journal of Computational Physics

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A finite element formulation to approximate the behavior of lipid membranes is proposed. The mathematical model incorporates tangential viscous stresses and bending elastic forces, together with the inextensibility constraint and the enclosed volume constraint. The membrane is discretized by a surface mesh made up of planar triangles, over which a mixed formulation (velocity-curvature) is built based on the viscous bilinear form (Boussinesq-Scriven operator) and the Laplace-Beltrami identity relating position and curvature. A semi-implicit approach is then used to discretize in time, with piecewise linear interpolants for all variables. Two stabilization terms are needed: The first one stabilizes the inextensibility constraint by a pressure-gradient-projection scheme (R. Codina and J. Blasco, Computer Methods in Applied Mechanics and Engineering 143:373-391, 1997), the second couples curvature and velocity to improve temporal stability, as proposed by Bänsch (Numerische Mathematik 88:203-235, 2001). The volume constraint is handled by a Lagrange multiplier (which turns out to be the internal pressure), and an analogous strategy is used to filter out rigid-body motions. The nodal positions are updated in a Lagrangian manner according to the velocity solution at each time step. An automatic remeshing strategy maintains suitable refinement and mesh quality throughout the simulation.Numerical experiments show the convergent and robust behavior of the proposed method. Stability limits are obtained from numerous relaxation tests, and convergence with mesh refinement is confirmed both in the relaxation transient and in the final equilibrium shape. Virtual tweezing experiments are also reported, computing the dependence of the deformed membrane shape with the tweezing velocity (a purely dynamical effect). For sufficiently high velocities, a tether develops which shows good agreement, both in its final radius and in its transient behavior, with available analytical solutions. Finally, simulation results of a membrane subject to the simultaneous action of six tweezers illustrate the robustness of the method.

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“…The experimental data about lipid membrane hereditariness that can be found in literature [45] show that the case of a purely elastic membrane represents the asymptotic condition of the mechanics of the lipid bilayer under a constant uniform stress. However, this circumstance is very seldom present in the physiological conditions of living cells, for which intracellular and/or extracellular fluids contributes to change the areal membrane stretch several times during cell lifetimes.…”

Section: The Mechanics Of Fractional Order Lipid Bilayersmentioning

confidence: 99%

“…Available experimental data [2,45,46] show that lipid bilayers present a time-dependent behavior depending on the in-plane anomalous viscous behavior exhibited by various lipid molecules at different temperatures.…”

Section: The Mechanics Of Fractional Order Lipid Bilayersmentioning

confidence: 99%

“…Several experimental observations on lipid monoand-bilayer [45] showed that the storage and loss modulus, namely G (p) and G (p), are proportional to the frequency through a power-law of frational order, i.e G (p) ∝ p β and G (p) ∝ p β+1 , where the exponent β depends on temperature and specific chemical composition of the biological structure.…”

Section: The Physical Description Of Lipid Membrane Hereditarinessmentioning

confidence: 99%

See 1 more Smart Citation

Fractional hereditariness of lipid membranes: Instabilities and linearized evolution

Deseri

Pollaci

Zingales

et al. 2016

Journal of the Mechanical Behavior of Biomedical Materials

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Phospholipid Bilayers are Viscoelastic

Cited by 12 publications

References 28 publications

The slow short-time motions of phospholipid molecules with a focus on the influence of multiple scattering and fitting artefacts

The slow short-time motions of phospholipid molecules with a focus on the influence of multiple scattering and fitting artefacts

A semi-implicit finite element method for viscous lipid membranes

Fractional hereditariness of lipid membranes: Instabilities and linearized evolution

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