Membrane elasticity effects on permeability measurements in vesicles

Chiruvolu, S.; Zasadzinski, Joseph A.

doi:10.1002/aic.690390413

Cited by 6 publications

(4 citation statements)

References 29 publications

(45 reference statements)

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“…Secondly, it may be due to the fact that the model presented in section 2.2 does not take into account the membrane elasticity. It has already been pointed out [25] that failing to account for membrane elasticity in the interpretation of the membrane permeability measurements in a similar experiment leads to an underestimate of membrane permeability. Our earlier estimates [7] however show that this correction amounts to only 2-3% and thus cannot explain the observed difference.…”

Section: Test Set Of Datamentioning

confidence: 94%

Determining membrane permeability of giant phospholipid vesicles from a series of videomicroscopy images

Peterlin

Jaklič

Pisanski

2009

Meas. Sci. Technol.

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Abstract.A technique for determining the permeability of a phospholipid membrane on a single giant unilamellar vesicle (GUV) is described, which complements the existing methods utilizing either a planar black lipid membrane or sub-micrometre-sized liposomes.A single GUV is transferred using a micropipette from a solution of a nonpermeable solute into an iso-osmolar solution of a solute with a higher membrane permeability. Osmotical swelling of the vesicle is monitored with a CCD camera mounted on a phase contrast microscope, and a sequence of images is obtained. On each image, the points on the vesicle contour are determined using Sobel filtering with adaptive binarization threshold, and from these, the vesicle radius is calculated with a great accuracy. From the time-dependence of the vesicle radius, the membrane permeability is obtained. Using a test set of data, the method provided a consistent estimate of the POPC membrane permeability for glycerol, P = 1.7 × 10 −8 m/s, with individual samples ranging from 1.61 × 10 −8 m/s to 1.98 × 10 −8 m/s. This value is ≈ 40% lower than the one obtained on similar systems. Possible causes for this discrepancy are discussed.

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Section: Test Set Of Datamentioning

confidence: 94%

Determining membrane permeability of giant phospholipid vesicles from a series of videomicroscopy images

Peterlin

Jaklič

Pisanski

2009

Meas. Sci. Technol.

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“…Since scattering techniques yield microstructure only indirectly by comparing the measured scattering pattern with a microstructural model, it is desirable to visualize microstructure directly in order to determine its qualitative nature. Cryo-transmission electron microscopy (cryo-TEM) 30,31 is suitable for visualization of wormlike micelles and used in the present study. Direct images with a resolution of about 3 nm may be obtained without staining or drying artifacts.…”

Section: Introductionmentioning

confidence: 99%

An Investigation of the Micellar Phase of Sodium Sulfopropyl Octadecyl Maleate in Aqueous Sodium Chloride Solutions by Light Scattering Techniques. Evidence of Nearly Rodlike Micelles

et al. 1996

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The micellar phase of sodium sulfopropyl octadecyl maleate (SSPOM) in aqueous solution in the presence of NaCl has been investigated by static and dynamic light scattering. Below 80 mmol/L NaCl, small micelles with a mean aggregation number of 180 and an effective ionization degree of 0.13 are detected. Their size is salt independent and they show a small shape asymmetry. At higher salt concentrations a spheroid-to-rod transition occurs and elongated micelles are detected. The light scattering measurements are interpreted by using a structural model of nearly rodlike particles. At 250 mmol/L NaCl the contour and persistence lengths are about 500 and 120 nm, respectively. For higher surfactant concentrations than 3 × 10-3 g/mL the scattering behavior features that of a network of entangled micelles. The measured data are described by simple power laws with exponents differing from those predicted for semidilute solutions of flexible chains which is suggested to result from the high stiffness of structures. The micelles are directly visualized by cryo-TEM.

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“…This net increase in bilayer tension is related to an increase in the membrane surface area, which is given by (Chiruvolu and Zasadzinski 1993) D K˛ (10.26) where K is the area expansion modulus of the bilayer and ' is the fractional increase in area of the bilayer. Assuming that the average area expansion modulus of a typical cell membrane vesicle is about 150 mN m 1 (Miyamoto et al 1988), Eqs.…”

Section: Functional Role Of Membrane-bound Receptorsmentioning

confidence: 99%

Water at Biological Phase Boundaries: Its Role in Interfacial Activation of Enzymes and Metabolic Pathways

Damodaran

2015

Subcellular Biochemistry

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Many life-sustaining activities in living cells occur at the membrane-water interface. The pertinent questions that we need to ask are, what are the evolutionary reasons in biology for choosing the membrane-water interface as the site for performing and/or controlling crucial biological reactions, and what is the key physical principle that is very singular to the membrane-water interface that biology exploits for regulating metabolic processes in cells? In this chapter, a hypothesis is developed, which espouses that cells control activities of membrane-bound enzymes through manipulation of the thermodynamic activity of water in the lipid-water interfacial region. The hypothesis is based on the fact that the surface pressure of a lipid monolayer is a direct measure of the thermodynamic activity of water at the lipid-water interface. Accordingly, the surface pressure-dependent activation or inactivation of interfacial enzymes is directly related to changes in the thermodynamic activity of interfacial water. Extension of this argument suggests that cells may manipulate conformations (and activities) of membrane-bound enzymes by manipulating the (re)activity of interfacial water at various locations in the membrane by localized compression or expansion of the interface. In this respect, cells may use the membrane-bound hormone receptors, lipid phase transition, and local variations in membrane lipid composition as effectors of local compression and/or expansion of membrane, and thereby local water activity. Several experimental data in the literature will be reexamined in the light of this hypothesis.

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Membrane elasticity effects on permeability measurements in vesicles

Cited by 6 publications

References 29 publications

Determining membrane permeability of giant phospholipid vesicles from a series of videomicroscopy images

Determining membrane permeability of giant phospholipid vesicles from a series of videomicroscopy images

An Investigation of the Micellar Phase of Sodium Sulfopropyl Octadecyl Maleate in Aqueous Sodium Chloride Solutions by Light Scattering Techniques. Evidence of Nearly Rodlike Micelles

Water at Biological Phase Boundaries: Its Role in Interfacial Activation of Enzymes and Metabolic Pathways

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