Miscibility Transitions and Lateral Compressibility in Liquid Phases of Lipid Monolayers

Keller, Sarah L.

doi:10.1021/la025891y

Cited by 31 publications

(36 citation statements)

References 33 publications

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“…For ideal behavior, the variation of the mole fractions results in a linear relation. Compressibility data were calculated for pure lipid monolayers at a given surface pressure π from the π-A isotherm using (Keller, 2003):…”

Section: Analysis Of Isothermsmentioning

confidence: 99%

Imaging of the domain organization in sphingomyelin and phosphatidylcholine monolayers

Prenner¹,

Honsek²,

Hoenig³

et al. 2007

Chemistry and Physics of Lipids

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The lateral organization of biomembranes has gained significant interest when the fluid mosaic model was challenged by the model of "lipid rafts". Several lipid classes like cholesterol and sphingolipids are considered to be essential for their formation. Here we investigate the lateral domain formation in binary mixtures of sphingomyelin and phosphatidylcholine. Both are major lipid components of lipoproteins and mammalian cell membranes at various molar ratios. Surface pressure-area isotherms and surface potential-area isotherms of monolayers composed of these lipids clearly indicated non-ideal mixing. In addition, Brewster angle microscopy provided a well-suited approach to image the formation of lateral domains. These images demonstrated that pure sphingomyelin forms very stable finger-like domains that exhibit a distinct internal organization suggesting an anisotropic orientation of the acyl side chains. Similar behavior was found for mixtures containing more than 60 mol% sphingomyelin. With increasing content of phosphatidylcholine the domain size decreased and the surface pressure, where domain formation occurred, increased. At lower sphingomyelin content (30-60 mol%) rather round-shaped, smaller domains were observed. Thus, the potential of sphingomyelin domains as potentially important building blocks for actual domains that could be building blocks for raft formation is suggested, even without the presence of cholesterol. In addition, these observations may suggest a role for the distinct molar ratio of these key lipids frequently found in physiologically relevant particles such as low and high density lipoproteins or the outer leaflet of the human erythrocyte membrane.

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Section: Analysis Of Isothermsmentioning

confidence: 99%

Imaging of the domain organization in sphingomyelin and phosphatidylcholine monolayers

Prenner¹,

Honsek²,

Hoenig³

et al. 2007

Chemistry and Physics of Lipids

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show abstract

“…From this, compressibility was calculated as −(∂A/∂π)/A. 18 Surface pressures were initially constant during compression of the monolayer and then rose above baseline values. This liftoff from the baseline was calculated as the mean molecular area at which surface pressure increased by 0.05 mN/m when the mean molecular area was changed by 0.5 Å 2 .…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

3-Hydroxybutyric Acid Interacts with Lipid Monolayers at Concentrations That Impair Consciousness

et al. 2013

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3-Hydroxybutyric acid (also referred to as β-hydroxybutyric acid or BHB), a small molecule metabolite whose concentration is elevated in type I diabetes and diabetic coma, was found to modulate the properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers when added to the subphase at clinical concentrations. This is a key piece of evidence supporting the hypothesis that the anesthetic actions of BHB are due to the metabolite's abilities to alter physical properties of cell membranes, leading to indirect effects on membrane protein function. Pressure-area isotherms show that BHB changes the compressibility of the monolayer and decrease the size of the two-phase coexistence region. Epi-fluorescent microscopy further reveals that the reduction of the coexistence region is due to the significant reduction in morphology of the liquid condensed domains in the two-phase coexistence region. These changes in monolayer morphology are associated with the diminished interfacial viscosity of the monolayers (measured using an interfacial stress rheometer), which gives insight as to how changes in phase and structure may contribute to membrane function.

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“…The analysis of the two-dimensional compressibility parameter as a function of surface pressure confirms this evolution in the organization state. This parameter is more accurate than an isotherm to characterize the LE-LC phase transition (Keller, 2003;Yu et al, 2002). The overall shape of the π-C s control curve (Fig.…”

Section: Effect Of Dsdna Interaction On Dogs Monolayer Interfacial Prmentioning

confidence: 99%

“…This finding suggests that the lower the C s value of a monolayer, the more difficult to deform it, the minimum C s value representing a highly rigid state. C s is directly related to the interfacial properties (Keller, 2003).…”

Section: Monolayer Techniques and Surface Pressure-area Measurementsmentioning

confidence: 99%

Development of a fluid functionalized lipidic matrix applied to direct in situ polynucleotide detection

Thomas

Blum

Girard-Egrot

2005

Biosensors and Bioelectronics

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Miscibility Transitions and Lateral Compressibility in Liquid Phases of Lipid Monolayers

Cited by 31 publications

References 33 publications

Imaging of the domain organization in sphingomyelin and phosphatidylcholine monolayers

Imaging of the domain organization in sphingomyelin and phosphatidylcholine monolayers

3-Hydroxybutyric Acid Interacts with Lipid Monolayers at Concentrations That Impair Consciousness

Development of a fluid functionalized lipidic matrix applied to direct in situ polynucleotide detection

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