Domain observation and molecular orientation of chiral dipalmitoylphosphatidylcholine monolayer by Brewster angle microscopy and Maxwell displacement current

Ou‐Yang, Wei; Yamamoto, Tetsuya; Aida, Takashi; Manaka, Takaaki; Iwamoto, Mitsumasa

doi:10.1016/j.tsf.2007.04.077

Cited by 15 publications

(18 citation statements)

References 15 publications

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“…The micrograph at 4 mN m –1 shows the onset of LC-phase formation, where the smaller condensed domains of pure DPPC tend to be circular and the larger ones exhibit a more complex geometry. As the monolayer is compressed further, the condensed domains increase in size and form the chiral, counterclockwise-twisted multilobed domains typically observed for l -DPPC . Compression to surface pressures above the LE–LC coexistence region leads to the gradual fusion of the condensed domains to form a homogeneous monolayer of pure DPPC (π = 45 mN m –1 image).…”

Section: Resultsmentioning

confidence: 97%

“…As the monolayer is compressed further, the condensed domains increase in size and form the chiral, counterclockwise-twisted multilobed domains typically observed for L-DPPC. 53 Compression to surface pressures above the LEÀLC coexistence region leads to the gradual fusion of the condensed domains to form a homogeneous monolayer of pure DPPC (π = 45 mN m À1 image). The inclusion of 0.2 mol % C 16 SAu NPs into the DPPC monolayer drastically alters the domain appearance (Figure 2B).…”

Section: Resultsmentioning

confidence: 99%

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Influence of Hydrophobic Alkylated Gold Nanoparticles on the Phase Behavior of Monolayers of DPPC and Clinical Lung Surfactant

Tatur

Badia

2011

Langmuir

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The effect of hydrophobic alkylated gold nanoparticles (Au NPs) on the phase behavior and structure of Langmuir monolayers of dipalmitoylphosphatidylcholine (DPPC) and Survanta, a naturally derived commercial pulmonary surfactant that contains DPPC as the main lipid component and hydrophobic surfactant proteins SP-B and SP-C, has been investigated in connection with the potential implication of inorganic NPs in pulmonary surfactant dysfunction. Hexadecanethiolate-capped Au NPs (C(16)SAu NPs) with an average core diameter of 2 nm have been incorporated into DPPC monolayers in concentrations ranging from 0.1 to 0.5 mol %. Concentrations of up to 0.2 mol % in DPPC and 16 wt % in Survanta do not affect the monolayer phase behavior at 20 °C, as evidenced by surface pressure-area (π-A) and ellipsometric isotherms. The monolayer structure at the air/water interface was imaged as a function of the surface pressure by Brewster angle microscopy (BAM). In the liquid-expanded/liquid-condensed phase coexistence region of DPPC, the presence of 0.2 mol % C(16)SAu NPs causes the formation of many small, circular, condensed lipid domains, in contrast to the characteristic larger multilobes formed by pure lipid. Condensed domains of similar size and shape to those of DPPC with 0.2 mol % C(16)SAu NPs are formed by compressing Survanta, and these are not affected by the C(16)SAu NPs. Atomic force microscopy images of Langmuir-Schaefer-deposited films support the BAM observations and reveal, moreover, that at high surface pressures (i.e., 35 and 45 mN m(-1)) the C(16)SAu NPs form honeycomb-like aggregates around the polygonal condensed DPPC domains. In the Survanta monolayers, the C(16)SAu NPs were found to accumulate together with the proteins in the liquid-expanded phase around the circular condensed lipid domains. In conclusion, the presence of hydrophobic C(16)SAu NPs in amounts that do not influence the π-A isotherm alters the nucleation, growth, and morphology of the condensed domains in monolayers of DPPC but not of those of Survanta. Systematic investigations of the effect of the interaction of chemically defined NPs with the lipid and protein components of lung surfactant on the physicochemical properties of surfactant films are pertinent to understanding how inhaled NPs impact pulmonary function.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Influence of Hydrophobic Alkylated Gold Nanoparticles on the Phase Behavior of Monolayers of DPPC and Clinical Lung Surfactant

Tatur

Badia

2011

Langmuir

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“…Experimental studies of monolayers at the air-water interface, using the technique of surface pressure-area (p-A) measurements, were obtained by intensive research on fatty acid monolayers. 3 Recently, much progress has been made due to the development of several kinds of methodologies, such as new experimental methods, [4][5][6][7] computer simulations and molecular models. [8][9][10] The advantage of a monolayer, particularly when compared to a bilayer, lies in its controllability.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of F-DPPC/DPPC mixed monolayers. Influence of subphase temperature on F-DPPC and DPPC monolayers

Toimil

Prieto

Miñones

et al. 2010

Phys. Chem. Chem. Phys.

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The surface behavior of two zwitterionic phospholipids: 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-[16-fluoropalmitoyl-phosphatidylcholine] (F-DPPC), has been investigated at the air-water interface at the temperature range from 10 to 30 °C. Surface pressure-area isotherms, BAM images and thickness-time curves were obtained for monolayers made from these pure phospholipids and from their mixtures.The comparative study of the behavior of both phospholipid monolayers with temperature showed some differences as the disappearance of the liquid expanded (LE)-liquid condensed (LC) phase transition at low temperatures for the DPPC but not for F-DPPC, because the F-DPPC monolayer is more expanded and more resistant to changes of temperature. On the other hand, film elasticity (C(s)(-1)) values calculated for both phospholipids show that the film condensation diminishes when the temperature increases, in accordance with the results obtained from surface pressure measurements.BAM images for F-DPPC monolayers recorded at different surface pressures and temperatures show the existence of numerous ovoid-like domains when the LE-LC phase transition is reached. However, in the LE and LC phases, homogeneous images were obtained. Time evolution of relative thickness along the compression of F-DPPC and DPPC monolayers shows similar behavior of both phospholipids, except at low temperatures.For DPPC/F-DPPC mixed systems, the plots of the mean molecular area as a function of F-DPPC mole fraction (X(F-DPPC)) indicated that, whatever the surface pressure, the experimental results match the theoretical values calculated from the additivity rule, a typical behavior for ideal mixed monolayers made of miscible components. This conclusion is confirmed from the values calculated for the free energy of excess (ΔG(exc)) of this system, which are practically zero, whatever the composition of the mixtures and the surface pressure at which ΔG(exc) values were calculated.

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“…The results obtained from BAM combined with surface pressure experiments confirmed that chiral discrimination effects within the surface monolayer may be employed for separating a racemic monolayer into domains of uniform chirality, i.e., l ‐DPPC liquid condensed domains, using a "catalytic" quantity of an enantiomeric molecule. Only a limited number of examples of this type are present in the literature so far . Since the pioneer work of Vollhardt and colleagues, many authors have addressed chirality in self‐assembled structures as emerging cooperatively from chirality at the molecular scale.…”

Section: Resultsmentioning

confidence: 99%

Separation of Enantiomers of a Phospholipid in Langmuir Monolayers by a New Selector

et al. 2015

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Domain observation and molecular orientation of chiral dipalmitoylphosphatidylcholine monolayer by Brewster angle microscopy and Maxwell displacement current

Cited by 15 publications

References 15 publications

Influence of Hydrophobic Alkylated Gold Nanoparticles on the Phase Behavior of Monolayers of DPPC and Clinical Lung Surfactant

Influence of Hydrophobic Alkylated Gold Nanoparticles on the Phase Behavior of Monolayers of DPPC and Clinical Lung Surfactant

A comparative study of F-DPPC/DPPC mixed monolayers. Influence of subphase temperature on F-DPPC and DPPC monolayers

Separation of Enantiomers of a Phospholipid in Langmuir Monolayers by a New Selector

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