Anomalous swelling of lipid bilayer stacks is caused by softening of the bending modulus

Chu, Nanjun; Kučerka, Norbert; Liu, Yufeng; Tristram-Nagle, Stephanie; Nagle, John F.

doi:10.1103/physreve.71.041904

Cited by 99 publications

(99 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The slope of the force-distance curve in the fluid phase is again smaller than in the gel phase and B is determined to B > 3.3 · 10 6 N/m 2 (interrupted by the bilayer rupture). All values for B agree quite well with and lie quite in the middle of the broad range of values reported in the literature (23,30,37,38). While the energy to compress the membrane stack is comparable in gel (ripple) and fluid phase, the stack is distinctly harder to compress in the range of critical swelling.…”

Section: Force Curvessupporting

confidence: 73%

Atomic force microscopy study of thick lamellar stacks of phospholipid bilayers

2008

View full text Add to dashboard Cite

We report an Atomic Force Microscopy (AFM) study on thick multi lamellar stacks of approx. 10 µm thickness (about 1500 stacked membranes) of DMPC (1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine) deposited on silicon wafers. These thick stacks could be stabilized for measurements under excess water or solution. From force curves we determine the compressional modulus B and the rupture force F r of the bilayers in the gel (ripple), the fluid phase and in the range of critical swelling close to the main transition. AFM allows to measure the compressional modulus of stacked membrane systems and values for B compare well to values reported in the literature. We observe pronounced ripples on the top layer in the P β ′ (ripple) phase and find an increasing ripple period Λ r when approaching the temperature of the main phase transition into the fluid L α phase at about 24 • C. Metastable ripples with 2Λ r are observed. Λ r also increases with increasing osmotic pressure, i.e., for different concentrations of polyethylene glycol (PEG).

show abstract

Section: Force Curvessupporting

confidence: 73%

Atomic force microscopy study of thick lamellar stacks of phospholipid bilayers

2008

View full text Add to dashboard Cite

show abstract

“…Using K A and d HH from our previous results, we obtain κ b ) 21.9 ( 1.6k B T. Experiments have measured 16.7k B T from X-ray data, 85 13.5k B T from pipet aspiration, 7 31.4k B T from thermally excited shape fluctuation, 86 and 32.1k B T from all-optical measurement. 87 Our estimate lies inside the range of the experimental values.…”

Section: Resultsmentioning

confidence: 62%

A Quantitative Coarse-Grain Model for Lipid Bilayers

et al. 2007

View full text Add to dashboard Cite

A simplified particle-based computer model for hydrated phospholipid bilayers has been developed and applied to quantitatively predict the major physical features of fluid-phase biomembranes. Compared with available coarse-grain methods, three novel aspects are introduced. First, the main electrostatic features of the system are incorporated explicitly via charges and dipoles. Second, water is accurately (yet efficiently) described, on an individual level, by the soft sticky dipole model. Third, hydrocarbon tails are modeled using the anisotropic Gay-Berne potential. Simulations are conducted by rigid-body molecular dynamics. Our technique proves 2 orders of magnitude less demanding of computational resources than traditional atomic-level methodology. Self-assembled bilayers quantitatively reproduce experimental observables such as electron density, compressibility moduli, dipole potential, lipid diffusion, and water permeability. The lateral pressure profile has been calculated, along with the elastic curvature constants of the Helfrich expression for the membrane bending energy; results are consistent with experimental estimates and atomic-level simulation data. Several of the results presented have been obtained for the first time using a coarse-grain method. Our model is also directly compatible with atomic-level force fields, allowing mixed systems to be simulated in a multiscale fashion.

show abstract

“…Note that this value is slightly lower than the value reported for DMPC under full hydration of d z = 66Å [18]. From MD simulations [9] ethanol was reported to decrease d z in DMPC/ethanol stacks.…”

contrasting

confidence: 44%

Ethanol enhances collective dynamics of lipid membranes

Kaye

Schmalzl²,

Nibali

et al. 2011

Phys. Rev. E

View full text Add to dashboard Cite

From inelastic neutron-scattering experiments and all atom molecular dynamics simulations we present evidence for a low-energy dynamical mode in the fluid phase of a 1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine (DMPC) bilayer immersed in a 5% water/ethanol solution. In addition to the well-known phonon that shows a liquidlike dispersion with energies up to 4.5 meV, we observe an additional mode at smaller energies of 0.8 meV, which shows little or no dispersion. Both modes show transverse properties and might be related to molecular motion perpendicular to the bilayer.

show abstract

Anomalous swelling of lipid bilayer stacks is caused by softening of the bending modulus

Cited by 99 publications

References 44 publications

Atomic force microscopy study of thick lamellar stacks of phospholipid bilayers

Atomic force microscopy study of thick lamellar stacks of phospholipid bilayers

A Quantitative Coarse-Grain Model for Lipid Bilayers

Ethanol enhances collective dynamics of lipid membranes

Contact Info

Product

Resources

About