Techniques in the Formation and Examination of “Black” Lipid Bilayer Membranes

Fettiplace, Robert; Gordon, L. G. M.; Hladky, Stephen B.; Requena, Jaime; Zingsheim, H. P.; Haydon, D. A.

doi:10.1007/978-1-4684-2907-7_1

Cited by 28 publications

(26 citation statements)

References 78 publications

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“…Thus, taking the perturbation in the form given by Eq. [14], the linear rupture time is dynamics of the system. We take H Å 1 / H in Eq.…”

Section: Electrohydrodynamic Modelmentioning

confidence: 99%

“…Instabilities are expected for perturbations with wavelength l ӷ h 0 (1, [14][15][16][17]. Then, we rescale again At the long-wavelength limit, the incompressibility condithe equations and boundary conditions introducing a small tion [2] reads parameter u Å h 0 /l appropriate for the long-wavelength approximation, and the total scaling reads £I xI / £I zI Å 0.…”

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confidence: 99%

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Nonlinear Dynamics of Lipid Films under Electric Forces

Ramos-de-Souza

Anteneodo²,

Costa-Pinto³

et al. 1997

Journal of Colloid and Interface Science

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We study the dynamics and rupture of lipid films perturbed in the symmetric mode squeezing through an electrohydrodynamical approach. The lipid phase and the two surrounding aqueous phases are considered as incompressible Newtonian viscous fluids submitted to van der Waals, steric, and electric body forces. A nonlinear evolution equation for the film thickness, at the long-wavelength limit, is obtained for two symmetric cases: a film with equally charged surfaces with no potential drop and a neutral film submitted to an external electric field. At the long-wavelength limit, the electric term only influences the film evolution when the electric field inside the film is nonvanishing. We solve numerically, as an initial value problem with periodic boundary conditions, the nonlinear evolution equation. The rupture time is obtained and compared with analytical estimates. Sufficiently strong steric forces prevent the film from narrowing beyond a minimum thickness leading the film to a steady state different from the planar one consistently with the nonlinear analytical approach. The presence of a transmembrane electric potential destabilizes the perturbed film as predicted by the linear and nonlinear approaches; however, as expected, destabilization is not relevant at physiological values of the potential drop.

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“…Thus, taking the perturbation in the form given by Eq. [14], the linear rupture time is dynamics of the system. We take H Å 1 / H in Eq.…”

Section: Electrohydrodynamic Modelmentioning

confidence: 99%

mentioning

confidence: 99%

Nonlinear Dynamics of Lipid Films under Electric Forces

Ramos-de-Souza

Anteneodo²,

Costa-Pinto³

et al. 1997

Journal of Colloid and Interface Science

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“…, 1965Everitt and Haydon 1968), which at the usual conductivities employed is some tens of microseconds; (c) a very small dispersion due to interfacial layers may be observed at very low frequencies ( < 100 Hz; Fettiplace et al 1971 ;Coster and Smith 1974;Perez and Wolfe 1989); (d) the presence of solvent increases the membrane thickness and hence decreases its capacitance from ca. 0.7 to some 0.4 ~tF cm -2 (Hanai et al 1964;White and Thompson 1973;Tien 1974;Fettiplace et al 1975;White 1978;Coster and Laver 1986;McIntosh et al 1989); (e) as expected for hydrocarbonlike materials, and neglecting ranges in which phase transitions occur, it is found that increases in temperature increase the thickness of BLM, and also the percent incorporation of organic solvent, both effects thereby serving to decrease the membrane capacitance by some (0.3-2% °C -1 overall (White 1970(White , 1975(White , 1978Benz et al 1975;Coster and Laver 1986).…”

Section: Introductionmentioning

confidence: 99%

Evidence from its temperature dependence that the ?-dielectric dispersion of cell suspensions is not due solely to the charging of a static membrane capacitance

1990

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1. A survey of the literature indicates that the apparent capacitance per unit area (Cm) of biological membranes is in general significantly greater than is that of 'artificial' phospholipid (black lipid) membranes (BLM). It is not possible, by quantitative arguments alone, to exclude that this simply reflects the idea that protein-containing biological membranes have a greater thickness than BLM. 2. The temperature-dependence of the membrane capacitance for both solvent-containing and solvent-free BLM is negative. However, where appropriate data are available, it appears that the capacitance of biological membranes has a positive temperature-dependence, indicating a qualitative difference between natural and artificial membranes. 3. Using a 4-terminal dielectric spectrometer, and the fitting program and electrode polarisation correction described in the accompanying paper, we have carried out a careful study of the temperature-dependence of the/?-dielectric dispersion of a unicellular eukaryote (Saccharomyces cerevisiae) and a prokaryote (Escherichia coli), 4. In the range 15-40 °C, the temperature-dependence of the/?-dielectric dispersion (and thus in principle of Cm) in S. cerevisiae and E. coli is respectively +0.13 and +0.35% (°C) -1. 5. Flow cytometric measurements indicate that the cell size of E. coli is unchanged in the temperature range studied. 6. These data strongly suggest that the/?-dielectric dispersion in cell suspensions is not due solely to the charging of a 'static' membrane capacitance. It is proposed that the positive temperature coefficient of the /?-dispersion reflects the contribution of temperaturedependent, partially restricted, lateral motions of the charged lipid and protein components of the cytoplasmic membrane.

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“…Such is the case for lipid bilayer membranes where admittance measurements have been used to determine the thickness of the hydrophobic core and also to give information on their structure and composition (Benz, Frdhlich, Liuger & Montal, 1975;Fettiplace, Gordon, Hladky, Requena, Zingsheim & Haydon, 1975;White, 1977;Ashcroft, Coster & Smith, 1981). Lipid bilayers have a very low conductance, so that the admittance at low frequencies has only a capacitative component.…”

Section: Introductionmentioning

confidence: 99%

The admittance of the squid giant axon at radio frequencies and its relation to membrane structure.

Haydon¹,

Urban²

1985

The Journal of Physiology

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SUMMARY1. The admittance of the squid giant axon membrane has been measured, using an intracellular electrode, at frequencies up to 40 MHz. The existence of a radio frequency dispersion, previously detected with extracellular electrodes (Cole, 1976) and attributed to the Schwann cell layer, has been confirmed and followed to higher frequencies.2. For a comparable method of analysis, membrane parameters similar to those given by Cole (1976) have been calculated. The radio frequency dispersion has a centre frequency at approximately 1-8 MHz, and the properties of a parallel combination of a 28 nF cm-2 capacity and a 3-3 Q cm2 resistance.3. When the axon membrane capacity is calculated, taking into account the radio frequency dispersion, as described above, the capacity remains frequency dependent throughout the range studied.4. If it is assumed that at high frequencies the axolemma capacity becomes constant at approximately the value for a lipid bilayer, a radio frequency dispersion is found which cannot be accounted for in terms of a simple equivalent circuit with two passive components, but appears to arise from a network with a distribution of relaxation times. This result could be consistent with the morphology of the Schwann cell layer.5. The radio frequency dispersion referred to in (4) can be described reasonably well by a circuit with two dispersions having centre frequencies of 250 kHz and 3-2 MHz respectively. The corresponding axolemma capacity (100-500 kHz) would be approximately 0-6 ,#F cm2.6. It is argued that between 50 and 100 kHz the geometrical capacity arising from the non-polar regions of the membrane is a major contributor to the axon membrane capacity, and that capacity variations arising from compositional changes in the lipid bilayer are best monitored in this frequency range.

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Techniques in the Formation and Examination of “Black” Lipid Bilayer Membranes

Cited by 28 publications

References 78 publications

Nonlinear Dynamics of Lipid Films under Electric Forces

Nonlinear Dynamics of Lipid Films under Electric Forces

Evidence from its temperature dependence that the ?-dielectric dispersion of cell suspensions is not due solely to the charging of a static membrane capacitance

The admittance of the squid giant axon at radio frequencies and its relation to membrane structure.

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