Surface pressure and surface potential study of a synthetic phospholipid at the air/water interface

Standish, M. M.; Pethica, B. A.

doi:10.1039/tf9686401113

Cited by 103 publications

(16 citation statements)

References 4 publications

(1 reference statement)

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“…This is especiMly true for a micelle containing a zwitterionic surfactant such as acylcarnitine. This is supported by a large number of studies on zwitterionic surfactants (26)(27)(28)(29)(30) which indicate that these compounds tend to be oriented at interfaces with the line connecting the two charged portions lying parallel to the interface.…”

Section: Discussionmentioning

confidence: 80%

Some micellar properties of long-chain acylcarnitines

Yalkowsky¹,

Zografi²

1970

Journal of Colloid and Interface Science

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The acid dissociation constants of long-chain esters of carnitine (5-hydroxy-~,trimethylammonium-butyrate) above the critical micelle concentration were determined potentiometrieally at several concentrations of added KC1. As the degree of protonation 5 increases the apparent pK values decrease owing to the increased positive charge on the micelle. The difference in pK between the neutral (zwitterionic) micelle and the value at any given ~ was used to determine the surface potential of the mieelle ,I* at that degree of protonation. At each degree of protonation the measured surface potential was related to the surface charge density ~ with the aid of the calculations of Loeb, Wiersema, and Overbeek for a spherical impenetrable particle. The surface potentials and surface charge densities of lauryl-, myristyl-, and pMmitylcarnitine are nearly identical at a given degree of protonation and ionic strength, and, as expected, increasing the ionic strength produces a decrease in the surface potential. From the partial molal volume of each surfactant in the mieelle and the calculated surface charge density it was possible to calculate the aggregation number n of the micelle. Good agreement was found between the calculated values of n and values obtained from light-scattering experiments at several ionic strengths and degrees of protonation.

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Section: Discussionmentioning

confidence: 80%

Some micellar properties of long-chain acylcarnitines

Yalkowsky¹,

Zografi²

1970

Journal of Colloid and Interface Science

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“…We presume the first, although impurity levels near 1% are difficult to quantify. Second, for pHϭ7Ϯ2 the polar head is uncharged, and therefore the surface pressure-area isotherms are not sensitive to small variations of pH or ionic milieu (Standish and Pethica, 1968). Third, the molecular area at high pressures, as deduced from the pressure-area isotherms, is given by the area of two aliphatic tails.…”

Section: B Phosphatidylethanolanolamines (Pe)mentioning

confidence: 99%

Structure and phase transitions in Langmuir monolayers

1999

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Lipid monolayers on the surface of water have been studied for over a hundred years, but in the last decade there has been a dramatic evolution in our understanding of the structures and phase transitions of these systems, driven by new experimental techniques and theoretical advances. In this review, dense monolayers of simple lipids are described in detail, including structures revealed by x-ray-diffraction experiments, computer simulations, molecular models, and a phenomenological theory of phase transitions. The effects of chirality and the structures of phospholipid monolayers are considered. Open questions and possible approaches to finding answers are discussed.[S0034-6861(99)00203-2] CONTENTS 815

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“…Figure 1A shows the compression curves for mixed cholesterol-dipalmitoyl cephalin monolayers spread on silica-free substrates of pH 6 at 20 ~ The pure cephalin monolayer exhibits a condensed film with a compressibility of 2.7 x 10 -3 cm. dyne -~ and a limiting area of 47 fk 2. molecule -z, which lies between the 45.2 A 2. molecule -1 reported by Standish and Pethica [13] on substrates containing 0.01 M NaCI, and the 49A 2 9 molecule -1 (Demel et al, [14]) or 48.3 A_ 2 9 molecule -1 (Hayashi et al, [15]) that have been found for films spread on substrates of pH 5.4. The mixed films likewise exhibited the liquid-condensed phase, with compressibilities of the same order as the pure cephalin and cholesterol films.…”

Section: Methodsmentioning

confidence: 83%

Cholesterol-dipalmitoyl cephalin and cholesterol-dilauroyl cephalin monolayers spread on silicic acid substrates

Miñones

Cid

Iribarnegaray

1988

Colloid & Polymer Sci

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Mixed cholesterol-dipalmitoyl cephalin and cholesterol-dilauroyl cephalin monolayers are slightly more expanded on silicic acid substrates than on silica-free substrates. Plotting the mean molecular area of the mixed monolayers against the mole fraction of cephalin shows that cholesterol produces condensation of the cephalin monolayer whether or not the substrate contains silicic acid, and the more expanded the pure phospholipid film, the greater is the condensation produced. These phenomena have been tentatively interpreted in terms of hydrophobic interactions between hydrocarbon chains and electrostatic interactions between the horizontally oriented polar groups of the cephalin molecules.

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Surface pressure and surface potential study of a synthetic phospholipid at the air/water interface

Cited by 103 publications

References 4 publications

Some micellar properties of long-chain acylcarnitines

Some micellar properties of long-chain acylcarnitines

Structure and phase transitions in Langmuir monolayers

Cholesterol-dipalmitoyl cephalin and cholesterol-dilauroyl cephalin monolayers spread on silicic acid substrates

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