Grazing incidence X-ray diffraction studies of condensed double-chain phospholipid monolayers formed at the soft air/water interface

Stefaniu, Cristina; Brezesinski, Gerald

doi:10.1016/j.cis.2014.01.005

Cited by 37 publications

(37 citation statements)

References 82 publications

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“…Furthermore, since fatty acids or phospholipids usually present unsaturations in the hydrocarbon chains, the study of mixtures of saturated and unsaturated compounds is of interest. Recent articles on fatty acid systems with mixed saturated-unsaturated hydrocarbon chains are those of [33,34], and on phospholipids systems with mixed saturated-unsaturated hydrocarbon chains are those of [35][36][37][38][39][40][41][42][43][44]. The main achievements reported in these works will be commented in the discussion section, in connection with the results of the present work.…”

Section: Introductionmentioning

confidence: 64%

Thermodynamic Behaviour of Mixed Films of an Unsaturated and a Saturated Polar Lipid. (Oleic Acid-Stearic Acid and POPC-DPPC)

Torrent‐Burgués

2018

Colloids and Interfaces

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Mixed fatty acids or mixed phospholipids systems with saturated-unsaturated hydrocarbon chains are of biological interest. In this work, the monolayers of oleic acid-stearic acid (OA-SA) and palmitoyloleoylphosphatidylcholine-dipalmitoylphosphatidylcholine (POPC-DPPC) have been studied. From the surface pressure-area isotherms, elastic modulus values and virial equation coefficients can be obtained. Thermodynamic treatment also yields excess (G E ) and mixing (∆G mix ) free energies. Results indicate positive G E values, that is, molecular interactions in the mixed films are less favourable, due to the presence of unsaturation; however, the mixture is slightly favourable due to the entropic factor that affords positive ∆G mix values. For the OA-SA system, a high SA content and surface pressure facilitate the phase separation, even though a certain miscibility between both components still remains. For the POPC-DPPC system, the most favourable mixing conditions occur for X POPC ≈ 0.4. For these mixed systems, the values of the elastic modulus are more similar to those of more fluid components (OA or POPC); analysis of the virial coefficients shows that the b 1 virial coefficient values lie between those of the individual components and are higher than values suitable for an ideal mixing.

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Section: Introductionmentioning

confidence: 64%

Thermodynamic Behaviour of Mixed Films of an Unsaturated and a Saturated Polar Lipid. (Oleic Acid-Stearic Acid and POPC-DPPC)

Torrent‐Burgués

2018

Colloids and Interfaces

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“…that is spread as a Langmuir monolayer (ML) at the vapor/solution (100 mM KCl and sub-mM FeCl 3 ) interface at low pH values at which the phosphate group is protonated, we employ surface sensitive X-ray diffraction and spectroscopic techniques [14][15][16][17][18][19] . Similar studies have been reported on various divalent ions with PC-based lipid monolayers albeit at relatively high salt concentrations (∼ 0.1 M; much higher than those in living cells), 20,21 showing changes in π − A isotherms but insignificant structural effects in the X-ray reflectivity or grazing incidence diffraction (GIXD).…”

Section: Introductionmentioning

confidence: 99%

Iron Ion and Iron Hydroxide Adsorption to Charge-Neutral Phosphatidylcholine Templates

et al. 2016

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Surface-sensitive X-ray scattering and spectroscopy techniques reveal significant adsorption of iron ions and iron-hydroxide (Fe(III)) complexes to a charge-neutral zwitterionic template of phosphatidylcholine (PC). The PC template is formed by a Langmuir monolayer of dipalmitoyl-PC (DPPC) that is spread on the surface of 2 to 40 μM FeCl3 solutions at physiological levels of KCl (100 mM). At 40 μM of Fe(III) as many as ∼3 iron atoms are associated with each PC group. Grazing incidence X-ray diffraction measurements indicate a significant disruption in the in-plane ordering of DPPC molecules upon iron adsorption. The binding of iron-hydroxide complexes to a neutral PC surface is yet another example of nonelectrostatic, presumably covalent bonding to a charge-neutral organic template. The strong binding and the disruption of in-plane lipid structure has biological implications on the integrity of PC-derived lipid membranes, including those based on sphingomyelin.

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“…9 At 30 °C, the cross-sectional area of Rad-PC-Rad (4) 20.2 Å 2 is in the expected range for rotator phases (for full data see Table 1 as well as Figure 3 and supporting information). 9,24…”

Section: Grazing Incidence-angle X-ray Diffraction (Gixd)mentioning

confidence: 99%

Synthesis and Biophysical Characterization of an Odd-Numbered 1,3-Diamidophospholipid

et al. 2018

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Nanomedicine suffers from low drug delivery efficiencies. Mechanoresponsive vesicles could provide an alternative way to release active compounds triggered by the basic physics of the human body. 1,3-Diamidophospholipids with C16 tails proved to be an effective building block for mechanoresponsive vesicles, but their low main phase transition temperature prevents an effective application in humans. As the main phase transition temperature of a membrane depends on the fatty acyl chain length, we synthesized a C17 homologue of a 1,3-diamidophospholipid: Rad-PC-Rad. The elevated main phase transition temperature of Rad-PC-Rad allows mechanoresponsive drug delivery at body temperature. Herein, we report the biophysical properties of Rad-PC-Rad monolayer and bilayer membranes. Rad-PC-Rad is an ideal candidate for advancing the concept of physically triggered drug release.

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Grazing incidence X-ray diffraction studies of condensed double-chain phospholipid monolayers formed at the soft air/water interface

Cited by 37 publications

References 82 publications

Thermodynamic Behaviour of Mixed Films of an Unsaturated and a Saturated Polar Lipid. (Oleic Acid-Stearic Acid and POPC-DPPC)

Thermodynamic Behaviour of Mixed Films of an Unsaturated and a Saturated Polar Lipid. (Oleic Acid-Stearic Acid and POPC-DPPC)

Iron Ion and Iron Hydroxide Adsorption to Charge-Neutral Phosphatidylcholine Templates

Synthesis and Biophysical Characterization of an Odd-Numbered 1,3-Diamidophospholipid

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