Kinetic studies on the interaction of phosphatidylcholine liposomes with Triton X-100

Alonso, Alicia; Urbaneja, Marı́a A.; Goñi, Félix M.; Carmona, Francisco Garcı́a; Cánovas, Fernando; Gómez‐Fernández, Juan C.

doi:10.1016/0005-2736(87)90301-4

Cited by 51 publications

(31 citation statements)

References 17 publications

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“…Our finding (Fig. 2) that vesicle growth occurs only at detergent concentrations bigger than the critical micelle concentrations confirms our prediction from kinetic studies [13] and explains the simultaneous increase in size and solubilization of liposomes. The solubilization phenomenon is interesting at this stage because, according to the results of Dennis [12], it only occurs at Triton X-100:phospholipid molar ratios of 2 or higher.…”

Section: Discussionsupporting

confidence: 89%

Structural changes induced by Triton X‐100 on sonicated phosphatidylcholine liposomes

Urbaneja

Goñi

Alonso

1988

European Journal of Biochemistry

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Solubilization of sonicated unilamellar vesicles by Triton X-100 is a complex process. Solubilization starts at low detergent concentrations, as compared to the case of large vesicles, and is accompanied by the simultaneous rapid formation of large multilamellar liposomes. Measurements of lipid and detergent distribution indicate that, at a 1 : 1 lipid: detergent mole ratio, about one-third of the lipid, with most of the detergent, is solubilized in the form of mixed micelles. The remaining two-thirds are in the form of multilamellar liposomes, virtually free of detergent. Higher detergent concentrations also bring about the solubilization of these liposomes.The study of surfactant effects on model and biomembranes is important from the point of view of molecular interactions as well as for biochemical technology [l, 21. We have recently examined the consequences of adding the non-ionic detergent Triton X-100, both at sublytic and lytic concentrations, to multilamellar phosphatidylcholine liposomes [3]. In the case of sonicated unilamellar vesicles we had previously shown [4, 51 that a variety of surfactants (Triton X-100, bile acids, octyl glucoside) induce an increase in size of sonicated vesicles. Such an effect may happen through a variety of mechanisms : lysis and reassembly, molecular exchange of phospholipids or vesicle-vesicle fusion, among others [6].The present paper intends to describe the complex structural changes of sonicated phosphatidylcholine liposomes in the presence of Triton X-100. We have combined ultrastructural and light-scattering observations with studies on the liberation of vesicle contents, and evaluated the incorporation of radioactive Triton X-100 to phospholipid bilayers and mixed micelles. As a result we can get a more detailed picture of the interaction of detergents with small unilamellar liposomes. This may have important implications in view of the potential use of sonicated phospholipid vesicles as drug carriers, since the extracellular body fluids contain natural amphiphiles that may act in a similar way as synthetic surfactants [7]. In addition, mixtures of sonicated liposomes and detergents are often used in membrane protein reconstitution procedures [8]. MATERIALS AND METHODSSonicated liposomes were prepared from egg-yolk phosphatidylcholine as described previously [4], except for calorimetric studies, where dipalmitoylglycerophosphocholine (Fluka) was used. The final phospholipid concentration was 1 mM unless otherwise stated. Detergent treatCorrespondence to A. Alonso, Departamento de Bioquimica, Facultad de Ciencias, Universidad del Pais Vasco, Apartado 644, E-48080 Bilbao, Spain Abbreviation. PamzGroPCho, dipalmitoylglycerophosphocholine. ments were also as described. Turbidity (as absorbance at 500nm) was measured in a UV5260 Beckman spectrophotometer against a buffer blank. Light scattering at 90 O was measured at 400 nm in a RF540 Shimadzu spectrofluorimeter. Negative-staining electron microscopy observations were also carried out according to [4].Vesicle leakage w...

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Section: Discussionsupporting

confidence: 89%

Structural changes induced by Triton X‐100 on sonicated phosphatidylcholine liposomes

Urbaneja

Goñi

Alonso

1988

European Journal of Biochemistry

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“…This hypothesis is motivated by the fact that non-ionic surfactants have very fast insertion and flip-flop rates (e.g. ∼100 ms for Triton-X 100 [2,20,55]) compared to the vesicle dynamics (∼ minute [15,16]), implying that surfactant saturation in the membrane occurs almost instantaneously. Consequently, we assume that the solubilization rate k is determined by the micelle formation kinetics.…”

Section: Model Formulationmentioning

confidence: 99%

Solubilization kinetics determines the pulsatory dynamics of lipid vesicles exposed to surfactant

Chabanon

Rangamani

2018

Biochimica et Biophysica Acta (BBA) - Biomembranes

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We establish a biophysical model for the dynamics of lipid vesicles exposed to surfactants. The solubilization of the lipid membrane due to the insertion of surfactant molecules induces a reduction of membrane surface area at almost constant vesicle volume. This results in a rate-dependent increase of membrane tension and leads to the opening of a micron-sized pore. We show that solubilization kinetics due to surfactants can determine the regime of pore dynamics: either the pores open and reseal within a second (short-lived pore), or the pore stays open up to a few minutes (long-lived pore). First, we validate our model with previously published experimental measurements of pore dynamics. Then, we investigate how the solubilization kinetics and membrane properties affect the dynamics of the pore and construct a phase diagram for short and long-lived pores. Finally, we examine the dynamics of sequential pore openings and show that cyclic short-lived pores occur with a period inversely proportional to the solubilization rate. By deriving a theoretical expression for the cycle period, we provide an analytical tool to estimate the solubilization rate of lipid vesicles by surfactants. Our findings shed light on some fundamental biophysical mechanisms that allow simple cell-like structures to sustain their integrity against environmental stresses, and have the potential to aid the design of vesicle-based drug delivery systems. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo.

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“…The selected surfactants were sodium dodecyl sulphate as a typical anionic surfactant widely used both in theoretical studies and practical applications; a sodium dodecyl ether sulphate to find the influence of the ethylene oxide groups on the anionic surfactant behavior; octyl phenolethoxilated with 10 units of ethylene oxide (Triton X-100) as a representative nonionic surfactant, used in the solubilization of phospholipid membranes (21)(22)(23)(24)(25); and dodecyl betaine as a representative of amphoteric surfactant frequently used in cosmetic formulations (26). When the surfactant concentrations that promote the half release of carboxyfluorescein from liposomes are plotted on the ordinate against the phospholipid concentrations on abscise, a linear relationship is observed.…”

Section: Abstract: Liposome-surfactants Interaction Partition Coeffmentioning

confidence: 99%

Permeability changes of phospholipid vesicles caused by surfactants

Maza

Ghosh

Parra

et al. 1991

J Americ Oil Chem Soc

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The partition coefficient at equilibrium of different surfactants between the aqueous phase and the lipid bilayer of small unilamellar vesicle (SUV) liposome has been determined. The release of the fluorescent agent 5-(6) carboxyfluorescein from the interior of liposomes, induced by a nonionic surfactant octylphenol ethoxylated with 10 units of ethylene oxide (Triton X-100), by two anionic surfactants --sodium dodecyl sulphate and sodium dodecyl ether sulphate --and by an amphoteric surfactant dodecyl betaine was studied at sub-solubilizing concentrations. The following increasing order of the partition coefficients obtained for each surfactant can be observed: Triton X-100 ~ sodium dodecyl ether sulphate sodium dodecyl sulphate ~ dodecyl betaine. There was a strong positive association between coefficient of partition and the ability of the different surfactants to modify the permeability ofliposomes. The importance of the presence of ethylene oxide units in the molecular structure of the surfactant in relation to alter the partition coefficient in front of SUV liposomes is indicated.

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Kinetic studies on the interaction of phosphatidylcholine liposomes with Triton X-100

Cited by 51 publications

References 17 publications

Structural changes induced by Triton X‐100 on sonicated phosphatidylcholine liposomes

Structural changes induced by Triton X‐100 on sonicated phosphatidylcholine liposomes

Solubilization kinetics determines the pulsatory dynamics of lipid vesicles exposed to surfactant

Permeability changes of phospholipid vesicles caused by surfactants

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