Adhesion of Lipid Membranes Mediated by Electrostatic and Specific Interactions

1997 ◽  
Vol 489 ◽  
Author(s):  
Christian W. Maier ◽  
Almuth Behrisch ◽  
Annette Kloboucek ◽  
Rudolf Merkel
Keyword(s):  
Lipid Membranes ◽  
Cell Adhesion Molecule ◽  
Lipid Vesicles ◽  
Membrane Properties ◽  
Specific Cell ◽  
Receptor Aggregation ◽  
Host Membrane ◽  
Aspiration Technique ◽  
Membrane Adhesion ◽  
Positively Charged

AbstractWe used the micropipet aspiration technique for a study of biomembrane adhesion. Adhesion was caused by contact site A, a highly specific cell adhesion molecule, reconstituted in lipid vesicles of DOPC with 5 %(mol/mol) DOPE-PEG2000. We found adhesion and subsequent receptor aggregation in the contact zone. Additionally, electrostatic modulation of membrane adhesion was studied. Whereas addition of the negatively charged lipid SOPS to the lecithin (SOPC) host membrane suppressed adhesion due to electrostatic repulsion, a positively charged lipid (DOTAP) was surprisingly ineffective. This might be due to either phase separation of the mixture or DOTAP changing other membrane properties as bending stiffness and the Hamaker constant.

scholarly journals Formation of Giant Lipid Vesicles in the Presence of Nonelectrolytes—Glucose, Sucrose, Sorbitol and Ethanol

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 945
Author(s):  
Qiong Wang ◽  
Ning Hu ◽  
Jincan Lei ◽  
Qiurong Qing ◽  
Jing Huang ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Cell Membrane ◽  
Lipid Membranes ◽  
Volume Fraction ◽  
Hydrodynamic Force ◽  
Lipid Vesicles ◽  
Ethanol Solution ◽  
Sugar Solution ◽  
Ethanol Content ◽  
Membrane Models

Lipid vesicles, especially giant lipid vesicles (GLVs), are usually adopted as cell membrane models and their preparation has been widely studied. However, the effects of some nonelectrolytes on GLV formation have not been specifically studied so far. In this paper, the effects of the nonelectrolytes, including sucrose, glucose, sorbitol and ethanol, and their coexistence with sodium chloride, on the lipid hydration and GLV formation were investigated. With the hydration method, it was found that the sucrose, glucose and sorbitol showed almost the same effect. Their presence in the medium enhanced the hydrodynamic force on the lipid membranes, promoting the GLV formation. GLV formation was also promoted by the presence of ethanol with ethanol volume fraction in the range of 0 to 20 percent, but higher ethanol content resulted in failure of GLV formation. However, the participation of sodium chloride in sugar solution and ethanol solution stabilized the lipid membranes, suppressing the GLV formation. In addition, the ethanol and the sodium chloride showed the completely opposite effects on lipid hydration. These results could provide some suggestions for the efficient preparation of GLVs.

Mechanics of membrane–membrane adhesion

2011 ◽  
Vol 16 (8) ◽  
pp. 872-886 ◽  
Author(s):  
Ashutosh Agrawal
Keyword(s):  
Lipid Vesicles ◽  
Spontaneous Curvature ◽  
Interface Conditions ◽  
Point Boundary ◽  
Lagrange Equations ◽  
Equilibrium Conditions ◽  
Numerical Studies ◽  
Curvature Elasticity ◽  
Equilibrium Shapes ◽  
Membrane Adhesion

Curvature elasticity is used to derive the equilibrium conditions that govern the mechanics of membrane–membrane adhesion. These include the Euler–Lagrange equations and the interface conditions which are derived here for the most general class of strain energies permissible for fluid surfaces. The theory is specialized for homogeneous membranes with quadratic ‘Helfrich’-type energies with non-uniform spontaneous curvatures. The results are employed to solve four-point boundary value problems that simulate the equilibrium shapes of lipid vesicles that adhere to each other. Numerical studies are conducted to investigate the effect of relative sizes, osmotic pressures, and adhesion-induced spontaneous curvature on the morphology of adhered vesicles.

scholarly journals The Structural Integrity of the Model Lipid Membrane during Induced Lipid Peroxidation: The Role of Flavonols in the Inhibition of Lipid Peroxidation

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 430 ◽  
Author(s):  
Anja Sadžak ◽  
Janez Mravljak ◽  
Nadica Maltar-Strmečki ◽  
Zoran Arsov ◽  
Goran Baranović ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Structural Changes ◽  
Structural Integrity ◽  
Lipid Membrane ◽  
Membrane Properties ◽  
Structural Reorganization ◽  
Unsaturated Lipids ◽  
Oxidative Attack

The structural integrity, elasticity, and fluidity of lipid membranes are critical for cellular activities such as communication between cells, exocytosis, and endocytosis. Unsaturated lipids, the main components of biological membranes, are particularly susceptible to the oxidative attack of reactive oxygen species. The peroxidation of unsaturated lipids, in our case 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), induces the structural reorganization of the membrane. We have employed a multi-technique approach to analyze typical properties of lipid bilayers, i.e., roughness, thickness, elasticity, and fluidity. We compared the alteration of the membrane properties upon initiated lipid peroxidation and examined the ability of flavonols, namely quercetin (QUE), myricetin (MCE), and myricitrin (MCI) at different molar fractions, to inhibit this change. Using Mass Spectrometry (MS) and Fourier Transform Infrared Spectroscopy (FTIR), we identified various carbonyl products and examined the extent of the reaction. From Atomic Force Microscopy (AFM), Force Spectroscopy (FS), Small Angle X-Ray Scattering (SAXS), and Electron Paramagnetic Resonance (EPR) experiments, we concluded that the membranes with inserted flavonols exhibit resistance against the structural changes induced by the oxidative attack, which is a finding with multiple biological implications. Our approach reveals the interplay between the flavonol molecular structure and the crucial membrane properties under oxidative attack and provides insight into the pathophysiology of cellular oxidative injury.

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

scholarly journals Large and Giant Unilamellar Vesicle(s) Obtained by Self-Assembly of Poly(dimethylsiloxane)-b-poly(ethylene oxide) Diblock Copolymers, Membrane Properties and Preliminary Investigation of Their Ability to Form Hybrid Polymer/Lipid Vesicles

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2013 ◽  
Author(s):  
Martin Fauquignon ◽  
Emmanuel Ibarboure ◽  
Stéphane Carlotti ◽  
Annie Brûlet ◽  
Marc Schmutz ◽  
...  
Keyword(s):  
Light Scattering ◽  
Ethylene Oxide ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Lipid Vesicles ◽  
Membrane Properties ◽  
Membrane Thickness ◽  
Hybrid Polymer ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

In the emerging field of hybrid polymer/lipid vesicles, relatively few copolymers have been evaluated regarding their ability to form these structures and the resulting membrane properties have been scarcely studied. Here, we present the synthesis and self-assembly in solution of poly(dimethylsiloxane)-block-poly(ethylene oxide) diblock copolymers (PDMS-b-PEO). A library of different PDMS-b-PEO diblock copolymers was synthesized using ring-opening polymerization of hexamethylcyclotrisiloxane (D3) and further coupling with PEO chains via click chemistry. Self-assembly of the copolymers in water was studied using Dynamic Light Scattering (DLS), Static Light Scattering (SLS), Small Angle Neutron Scattering (SANS), and Cryo-Transmission Electron Microscopy (Cryo-TEM). Giant polymersomes obtained by electroformation present high toughness compared to those obtained from triblock copolymer in previous studies, for similar membrane thickness. Interestingly, these copolymers can be associated to phospholipids to form Giant Hybrid Unilamellar Vesicles (GHUV); preliminary investigations of their mechanical properties show that tough hybrid vesicles can be obtained.

Different Effects of Di- and Triphenyltin Compounds on Lipid Bilayer Dithionite Permeabilization

2000 ◽  
Vol 55 (9-10) ◽  
pp. 758-763 ◽  
Author(s):  
Janina Gabrielska ◽  
Teresa Kral ◽  
Marek Langner ◽  
Stanislaw Przestalski
Keyword(s):  
Molecular Structure ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Membrane Properties ◽  
Human Environment ◽  
Vesicle Size ◽  
Phenyl Rings ◽  
Positively Charged ◽  
Steric Constraints ◽  
Quenching Assay

Abstract Phenyltins are chemicals widely used in industry, hence their occurrence in the human environment is frequent and widespread. Such compounds include hydrophobic phenyl rings bonded to positively charged tin. This molecular structure makes them capable of adsorbing onto and penetrating through biological membranes, hence they are potentially hazardous. Two such compounds, diphenyltin and triphenyltin, show different steric constraints when interacting with the lipid bilayer. It has been demonstrated that these compounds are positioned at different locations within model lipid bilayers, causing dissimilarity in their ability to affect membrane properties. In this paper we present a study regarding the ability of these two phenyltins to facilitate the transport of S2O4-2 ions across the lipid bilayer, evaluated by a fluorescence quenching assay. In concentration range of up-to 60 μm those compounds do not affect lipid bilayer topology, when evaluated by vesicle size distribution. Both phenyltins facilitate the transfer of S2O4-2 across the model lipid bilayer, but the dependence of dithionite transport on phenyltin concentration is different for both. In principle, above 20 μm triphenyltin is more efficient in transfering ions across the lipid bilayer than diphenyltin.

scholarly journals Nonequilibrium fluctuations of lipid membranes by the rotating motor protein F1F0-ATP synthase

2017 ◽  
Vol 114 (43) ◽  
pp. 11291-11296 ◽  
Author(s):  
Víctor G. Almendro-Vedia ◽  
Paolo Natale ◽  
Michael Mell ◽  
Stephanie Bonneau ◽  
Francisco Monroy ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Lipid Membranes ◽  
Lipid Vesicles ◽  
Proton Pumping ◽  
Collective Effects ◽  
Coupling Mechanism ◽  
Nonequilibrium Fluctuations ◽  
Membrane Fluctuations ◽  
Lipid Environment ◽  
Curved Membrane

ATP synthase is a rotating membrane protein that synthesizes ATP through proton-pumping activity across the membrane. To unveil the mechanical impact of this molecular active pump on the bending properties of its lipid environment, we have functionally reconstituted the ATP synthase in giant unilamellar vesicles and tracked the membrane fluctuations by means of flickering spectroscopy. We find that ATP synthase rotates at a frequency of about 20 Hz, promoting large nonequilibrium deformations at discrete hot spots in lipid vesicles and thus inducing an overall membrane softening. The enhanced nonequilibrium fluctuations are compatible with an accumulation of active proteins at highly curved membrane sites through a curvature−protein coupling mechanism that supports the emergence of collective effects of rotating ATP synthases in lipid membranes.

Wet chemical modification of PTFE implant surfaces with a specific cell adhesion molecule

2002 ◽  
pp. 2568-2569 ◽  
Author(s):  
Christoph Löhbach ◽  
Udo Bakowsky ◽  
Carsten Kneuer ◽  
Dieter Jahn ◽  
Thomas Graeter ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Chemical Modification ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Specific Cell ◽  
Wet Chemical

Reconstitution of the complement channel into lipid vesicles and planar bilayers starting from the fluid phase complex

1985 ◽  
Vol 5 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Gianfranco Menestrina ◽  
Flavia Pasquali
Keyword(s):  
Lipid Bilayers ◽  
Membrane Attack Complex ◽  
Fluid Phase ◽  
Lipid Vesicles ◽  
Ionic Channels ◽  
Single Channels ◽  
Planar Bilayers ◽  
Low Concentrations ◽  
Host Membrane ◽  
Phase Complex

Proteolysis of the fluid phase complement complex SC5b-9 transforms it into an arnphiphilic molecule which resembles the membrane attack complex of complement and reconstitutes into lipid vesicles. Complement-containing vesicles prepared in this way can be made to fuse with planar lipid bilayers transferring their protein content to the host membrane. Massive conductance increases can thus be observed, which are due to the insertion of a large number of ionic channels into the membrane. Using low concentrations of vesicles, single channels can be studied.

scholarly journals Archaeosome Vaccine Adjuvants Induce Strong Humoral, Cell-Mediated, and Memory Responses: Comparison to Conventional Liposomes and Alum

2000 ◽  
Vol 68 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Lakshmi Krishnan ◽  
Chantal J. Dicaire ◽  
Girishchandra B. Patel ◽  
G. Dennis Sprott
Keyword(s):  
Immune Responses ◽  
Lipid Vesicles ◽  
Interleukin 4 ◽  
Molar Ratio ◽  
Cell Mediated Immunity ◽  
Specific Cell ◽  
Vaccine Adjuvants ◽  
Strong Response ◽  
Freund’S Adjuvant ◽  
Freund's Adjuvant

ABSTRACT Ether glycerolipids extracted from various archaeobacteria were formulated into liposomes (archaeosomes) possessing strong adjuvant properties. Mice of varying genetic backgrounds, immunized by different parenteral routes with bovine serum albumin (BSA) entrapped in archaeosomes (∼200-nm vesicles), demonstrated markedly enhanced serum anti-BSA antibody titers. These titers were often comparable to those achieved with Freund's adjuvant and considerably more than those with alum or conventional liposomes (phosphatidylcholine-phosphatidylglycerol-cholesterol, 1.8:0.2:1.5 molar ratio). Furthermore, antigen-specific immunoglobulin G1 (IgG1), IgG2a, and IgG2b isotype antibodies were all induced. Association of BSA with the lipid vesicles was required for induction of a strong response, and >80% of the protein was internalized within most archaeosome types, suggesting efficient release of antigen in vivo. Encapsulation of ovalbumin and hen egg lysozyme within archaeosomes showed similar immune responses. Antigen-archaeosome immunizations also induced a strong cell-mediated immune response: antigen-dependent proliferation and substantial production of cytokines gamma interferon (Th1) and interleukin-4 (IL-4) (Th2) by spleen cells in vitro. In contrast, conventional liposomes induced little cell-mediated immunity, whereas alum stimulated only an IL-4 response. In contrast to alum and Freund's adjuvant, archaeosomes composed of Thermoplasma acidophilum lipids evoked a dramatic memory antibody response to the encapsulated protein (at ∼300 days) after only two initial immunizations (days 0 and 14). This correlated with increased antigen-specific cell cycling of CD4+ T cells: increase in synthetic (S) and mitotic (G2/M) and decrease in resting (G1) phases. Thus, archaeosomes may be potent vaccine carriers capable of facilitating strong primary and memory humoral, and cell-mediated immune responses to the entrapped antigen.

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