The main transition of dipalmitoylphosphatidylcholine monolayers: A liquid expanded to solid condensed high order transformation

Denicourt, Normand; Tancrède, Pierre; Teissié, Justin

doi:10.1016/0301-4622(93)e0066-e

Cited by 18 publications

(13 citation statements)

References 34 publications

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“…Experimentally, the transition region has been shown to exhibit an expanded to condensed phase transition, where the tilt of the palmitoyl chains of the phospholipid become more perpendicular to the air-water interface. This transition has been observed using various atomic resolution imaging methods of such films, as well as using neutron and grazing angle X-ray diffraction [22,23].…”

Section: Introductionmentioning

confidence: 90%

Molecular dynamics simulations of lung surfactant lipid monolayers

Rose

Rendell

Lee

et al. 2008

Biophysical Chemistry

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Section: Introductionmentioning

confidence: 90%

Molecular dynamics simulations of lung surfactant lipid monolayers

Rose

Rendell

Lee

et al. 2008

Biophysical Chemistry

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“…The different orientations of the coexisting highly ordered phases affect the LAURDAN position and hence the probe's excitation efficiency (see text). from DPPC monolayers have suggested that a loss of the hydration shell of the lipid head group occurs at high surface pressures when the lipids enter a solid-like phase without further change of the chain orientations from the condensed phase (Brumm et al, 1994;Denicourt et al, 1994). However, this last phase transition in DPPC monolayers is not detectable in the phase transition isotherms (Brumm et al, 1994;Kaganer et al, 1999) in contrast to that found in porcine surfactant monolayers at high packing densities .…”

Section: Gel Phase In Bles Bilayersmentioning

confidence: 99%

Segregation of Saturated Chain Lipids in Pulmonary Surfactant Filmsand Bilayers

Nag

Pao

Harbottle

et al. 2002

Biophysical Journal

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The physical properties of organized system (bilayers and monolayers at the air water interface) composed of bovine lipid extract surfactant (BLES) were studied using correlated experimental techniques. 6-Dodecanoyl-2-dimethylamino-naphthalene (LAURDAN)-labeled giant unilamelar vesicles (mean diameter approximately 30 microm) composed of BLES were observed at different temperatures using two-photon fluorescence microscopy. As the temperature was decreased, dark domains (gel-like) appeared at physiological temperature (37 degrees C) on the surface of BLES giant unilamelar vesicles. The LAURDAN two-photon fluorescent images show that the gel-like domains span the lipid bilayer. Quantitative analysis of the LAURDAN generalized polarization function suggests the presence of a gel/fluid phase coexistence between 37 degrees C to 20 degrees C with low compositional and energetic differences between the coexisting phases. Interestingly, the microscopic scenario of the phase coexistence observed below 20 degrees C shows different domain's shape compared with that observed between 37 degrees C to 20 degrees C, suggesting the coexistence of two ordered but differently organized lipid phases on the bilayer. Epifluorescence microscopy studies of BLES monomolecular films doped with small amounts of fluorescent lipids showed the appearance and growth of dark domains (liquid condensed) dispersed in a fluorescent phase (liquid expanded) with shapes and sizes similar to those observed in BLES giant unilamelar vesicles. Our study suggests that bovine surfactant lipids can organize into discrete phases in monolayers or bilayers with equivalent temperature dependencies and may occur at physiological temperatures and surface pressures equivalent to those at the lung interface.

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“…1 The lipid chains tilt such that the projected area of the hydrocarbon chains in the plane parallel to the water surface matches that of the headgroups. 5 Upon decompression (AϾ0.47 nm 2 ) the C phase coexists 7 with a gel-like 8 liquid condensed ͑LC͒ phase 7 in which lipid chains have gauche defects 3 but are still aligned. 1 Between 0.50 and 0.80 nm 2 /molecule the LC phase coexists with a more disora͒ Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Simulation studies of pore and domain formation in a phospholipid monolayer

Knecht

Müller

Bonn

et al. 2004

The Journal of Chemical Physics

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Simulation studies of pore and domain formation in a phospholipid monolayer.Knecht, V.; Müller, M.; Bonn, M.; Marrink, S.J.; Mark, A.E. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Despite extensive study the phase behavior of phospholipid monolayers at an air-water interface is still not fully understood. In particular recent vibrational sum-frequency generation ͑VSFG͒ spectra of DPPC monolayers as a function of area density show a sharp transition in the order of the lipid chains at 1.10 nm 2 /molecule. This is in a region where the lateral pressure as a function of area is effectively constant. We have investigated the nature of this transition by studying the phase behavior of DPPC monolayers as a function of area density using molecular-dynamics simulations. The changes in order within the monolayer as a function of area density correlate well with the experimental signal. At 0.58 nm 2 /molecule we observe the onset of lateral separation of highly ordered and disordered lipids, indicating the coexistence of a gel-like liquid condensed and a fluidlike liquid expanded phase. At 0.97 nm 2 /molecule the monolayer ruptures, marking the onset of the liquid-gas ͑G͒ coexistence region. This is much earlier than suggested by fluorescence microscopy results and implies that at the point of rupture, the initial pores have an equilibrium size smaller than ϳ500 nm in diameter. The rupture of the monolayer leads to a sharp increase in the overall lipid order that explains the sharp transition observed in the VSFG measurements. VSFG measurements thus may represent a sensitive means to determine the onset of the liquid-gas ͑G͒ coexistence region for such systems.

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The main transition of dipalmitoylphosphatidylcholine monolayers: A liquid expanded to solid condensed high order transformation

Cited by 18 publications

References 34 publications

Molecular dynamics simulations of lung surfactant lipid monolayers

Molecular dynamics simulations of lung surfactant lipid monolayers

Segregation of Saturated Chain Lipids in Pulmonary Surfactant Filmsand Bilayers

Simulation studies of pore and domain formation in a phospholipid monolayer

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