Using Ionic Strength to Control Liquid-Ordered/Liquid-Disordered Separation

Seu, Kalani J.; Lamberson, Emily R.; Hovis, Jennifer S.

doi:10.1021/jp070624s

Cited by 4 publications

(4 citation statements)

References 17 publications

(38 reference statements)

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“…These holelike structures were confirmed to be three-dimensional (3D) bubbles by adjusting the Z plane of the microscope focus. These 3D bilayer structures are similar to earlier structures created by Hovis and co-workers, and recently by Goertz et al − The later work showed very similar 3D structures in POPC bilayers at the extreme low and high pHs. In our case, the formation of 3D bubbles is likely due to the protonation of the glass substratum, which altered the stability of bilayers interacting with the substrates.…”

Section: Resultssupporting

confidence: 89%

Lipid Bilayer Templated Gold Nanoparticles Nanoring Formation Using Zirconium Ion Coordination Chemistry

et al. 2011

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We used positively charged lipids to prepare lipid bilayer assemblies (LBAs) upon which we assembled negatively charged gold nanoparticles (AuNPs). Treatment of the assembly with zirconium chloride resulted in the formation of nanorings of the diameters inversely related to the zirconium ion concentration. The nanorings were attributed to the zirconium ion coordinated AuNPs formed during the lipid bilayer budding process promoted by the acid effect of zirconium chloride. Nanoring organization was also dependent on the fluidity of lipid bilayers, an indication of LBA-assisted nanomaterials organization. We suggest that such bioorganic-inorganic hybrid assemblies coupled to unique topological and morphological variations might be useful as stimuli-responsive sensors or storage compartments for proteins or drugs.

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Section: Resultssupporting

confidence: 89%

Lipid Bilayer Templated Gold Nanoparticles Nanoring Formation Using Zirconium Ion Coordination Chemistry

et al. 2011

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“…There are several possible explanations: One, there is a higher concentration of PA in the upper leaflet, and separation only occurs in that leaflet. To address this, we replaced the tail-labeled NBD PC with head-labeled Texas Red DHPE, which can be quenched using iodine. , Changing the probe did not alter the separation behavior. Addition of 500 mM KI resulted in a loss of ∼50% of the fluorescence in both regions, i.e., the pattern remained visible (Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Controlling the Charge and Organization of Anionic Lipid Bilayers: Effect of Monovalent and Divalent Ions

2007

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It is shown that the organization of lipid bilayers containing phosphatidic acid (PA) and phosphatidlycholine (PC) can be controlled by altering the monovalent and divalent ion concentrations. At high pH and/or calcium concentration, 1:1 Ca(2+)-PA(2-) complexes form; these complexes demix, and PA-rich and PC-rich regions are observable with epifluorescence microscopy. The results are compared with predictions from electrostatic theory. It is noted that the complex formation correlates in a roughly linear fashion with the monovalent/divalent ion ratio, a parameter that cells adjust.

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“…Partial phase segregation of lipid species could, e.g., be driven by local variations in ionic charge known to have a stronger attraction on certain lipids and could induce curvature. 25,55 The local high concentration of cations at the substrate interface could in itself impose a higher curvature on one side of the membrane from variations in electrostatic screening across the membrane, as has been recently demonstrated. 55,56 An increased water coupling of the QCM-D is to be expected if this causes E. coli SLB to increasingly undulate.…”

Section: A E Coli Total Lipid Extract Slbmentioning

confidence: 91%

Formation of supported bacterial lipid membrane mimics

Merz¹,

Knoll²,

Textor³

et al. 2008

Biointerphases

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In recent years, a large effort has been spent on advancing the understanding of how surface-supported membranes are formed through vesicle fusion. The aim is to find simple model systems for investigating biophysical and biochemical interactions between constituents of cell membranes and, for example, drugs and toxins altering membrane function. Designing and controlling the self-assembly of model membranes onto sensor substrates thus constitutes an important field of research, enabling applications in, e.g., drug screening, dynamic biointerfaces, artificial noses, and research on membrane-active antibiotics. The authors have developed and investigated the formation of strongly negatively charged supported lipid membranes which systematically mimic bacterial membrane composition on three important biosensor materials: SiO2, TiO2, and indium tin oxide. By tuning the electrostatic interaction through balancing the lipid vesicle charge with the ionic strength of Ca2+ as a fusion promoter, the authors have optimized the self-assembly and obtained new insights into the details of lipid vesicle-surface interaction. The results will be useful for future development and application of specialized lipid membrane surface coatings prepared from complex lipid compositions. The adsorption processes were characterized by a quartz crystal microbalance with dissipation monitoring, optical waveguide lightmode spectroscopy, and fluorescence recovery after photobleaching, which allowed the determination of formation also of nonplanar supported lipid membranes.

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Using Ionic Strength to Control Liquid-Ordered/Liquid-Disordered Separation

Cited by 4 publications

References 17 publications

Lipid Bilayer Templated Gold Nanoparticles Nanoring Formation Using Zirconium Ion Coordination Chemistry

Lipid Bilayer Templated Gold Nanoparticles Nanoring Formation Using Zirconium Ion Coordination Chemistry

Controlling the Charge and Organization of Anionic Lipid Bilayers: Effect of Monovalent and Divalent Ions

Formation of supported bacterial lipid membrane mimics

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