Temperature dependence of interfacial fluctuations of polymerized fatty acid salt multilayers

Hu, Shuxin; Li, Xiuhong; Jia, Quanjie

doi:10.1063/1.1865952

Cited by 10 publications

(12 citation statements)

References 50 publications

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“…The electron density profiles (EDP) of the lipid bilayers in different phases can be reconstructed using a method proposed by Salditt et al , Briefly, the EDP of a bilayer can be refined from the X-ray diffraction data via normalρ false( z false) = ∑ 1 M f ( q m ) cos ( 2 π m z / d ) where f ( q m ) is the form factor of the bilayer, d is the interbilayer distance of the multilamellar membrane system, and m running from 1 to M is the index of the Bragg peaks. The magnitudes of f ( q m ) are determined from the intensities of the Bragg peaks, I ( q ) ∝ | ∑ 0 N f n e i q n d | 2 / q 2 where f 0 = f s is the reflection of the substrate and f n = f ( q )exp(− idq /2).…”

Section: Resultsmentioning

confidence: 99%

Structure and Phase Transformation of Oligodeoxynucleotide/Lipid Lipoplexes on Solid Supports

Lü

2010

Langmuir

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Lipoplexes are composed of lipids and nucleic acids and have an ordered multilamellar structure with a periodic 1D array of parallel nucleic acid strands in the lipid bilayers. We report a low-angle X-ray diffraction study on solid-supported lipoplex films composed of synthetic single-stranded oligodeoxynucleotides (ssODN) and lipids. The ssODN molecules distribute sparsely in the headgroup regions when the weight concentration of the ssODN in the lipoplex is low. The lipoplex separates into two phases, an ODN-poor phase and an ODN-rich phase, when the weight concentration of the ssODN is increased beyond a level at which the ssODN molecules contact each other so that some regions of the lipid bilayers must accommodate two layers of the ssODN. The phase separation is a result of the fusion of such regions to minimize the total interfacial energy of the system. The ssODN molecules distort the lipid bilayers in the ODN-poor phase. The local area per lipid molecule is increased by the distortions so that the interbilayer distance of the lipoplex film is smaller than that of the lipid film without the ssODN. The ODN-rich phase has a much larger interbilayer distance because two layers of ssODN are intercalated into each lipid bilayer. The ssODN molecules are tightly compacted, and the lipid bilayers are not distorted in the ODN-rich phase.

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Section: Resultsmentioning

confidence: 99%

Structure and Phase Transformation of Oligodeoxynucleotide/Lipid Lipoplexes on Solid Supports

Lü

2010

Langmuir

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“…The EDP can be obtained by theoretical simulation of the diffraction data where f ( q m ) is the form factor of the bilayer, d is the period of the multilayer, and m running from 1 to M is the index of the Bragg peaks . The magnitudes of f ( q m ) are determined from the intensities at the Bragg peaks, where f 0 = f S is the reflection of the substrate and f n = f ( q ) exp(− idq /2).…”

Section: Resultsmentioning

confidence: 99%

“…The magnitudes of f ( q m ) are determined from the intensities at the Bragg peaks, where f 0 = f S is the reflection of the substrate and f n = f ( q ) exp(− idq /2). Due to the mirror plane symmetry of the bilayers, the phases of f ( q m ) are reduced to their positive/negative signs only, facilitating the phase problem enormously . The method has been widely used to refine the structure of phospholipid bilayers.…”

Section: Resultsmentioning

confidence: 99%

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Electrochemical Growth of Highly Oriented Organic−Inorganic Superlattices Using Solid-Supported Multilamellar Membranes as Templates

Xing

et al. 2006

J. Am. Chem. Soc.

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Controllable depositing of relatively thick inorganic sublayers into organic templates to fabricate organic-inorganic superlattices is of great importance. We report a novel approach to fabricating phospholipid/Ni(OH)(2) superlattices by electrochemical deposition of the inorganic component into solid-supported multilamellar templates. The well-ordered and highly oriented multilamellar templates are produced by spreading small drops of lipid solution on silicon surfaces and letting the solvent evaporate slowly. The templates which are used as working electrodes preserve the lamellar structure in the electrolyte solution. The resulting superlattices are highly oriented. The thickness of the nickel hydroxide is controlled by the concentration of nickel ions in the electrolyte bath. The electron density profiles derived from the X-ray diffraction data reveal that the thickness of the nickel hydroxide sublayers increases from 15 to 27 A as the concentration of nickel nitrate increases from 0.005 mol/L to 0.08 mol/L. We expect that the new method can be extended to depositing a variety of inorganic components including metals, oxides, and semiconductors.

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“…Due to the mirror plane symmetry of the bilayers, the phases of f͑q z,m ͒ are reduced to their positive/ negative signs only, facilitating the phase problem. 13,24,25 …”

Section: Methodsmentioning

confidence: 99%

Phase separation of phospholipid multilayers incorporated with cell penetrating peptides

et al. 2011

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We used X-ray reflectivity to investigate the structures of phospholipid multilayers with transcription-activating-factor-derived peptide ͑TDP͒ as a function of the membrane charge density. Mixed phospholipid multilayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine ͑DPPC͒ and 1,2-dipalmitoyl -sn-glycero-3-phosphoserine ͑DPPS͒ with different mixing ratios ͑C:S͒ were used to elucidate the various charge densities in a plasma membrane. We fixed the peptide/lipid molar ratio ͑P/L͒ and varied the DPPC/DPPS molar ratio in the mixed multilayer. In the pure DPPC multilayer, the incorporation of TDP had nearly no effect on the bilayer thickness of the mixed lipid multilayer. However, in the mixed DPPC/DPPS multilayer, the incorporation of TDP decreased the bilayer thickness, suggesting that the TDP peptide had a stronger interaction with DPPS than with DPPC and caused disorder in the lamellar structure. Combining this with the refined X-ray reflectivity ͑XR͒ data, we concluded that the TDP existed more in the headgroup region of the TDP-induced segregated DPPS in the mixed multilayer and caused significant membrane thinning.

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Temperature dependence of interfacial fluctuations of polymerized fatty acid salt multilayers

Cited by 10 publications

References 50 publications

Structure and Phase Transformation of Oligodeoxynucleotide/Lipid Lipoplexes on Solid Supports

Structure and Phase Transformation of Oligodeoxynucleotide/Lipid Lipoplexes on Solid Supports

Electrochemical Growth of Highly Oriented Organic−Inorganic Superlattices Using Solid-Supported Multilamellar Membranes as Templates

Phase separation of phospholipid multilayers incorporated with cell penetrating peptides

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