Production of large unilamellar vesicles by a rapid extrusion procedure. Characterization of size distribution, trapped volume and ability to maintain a membrane potential

Hope, Michael J.; Bally, Marcel B.; Webb, G. A.; Cullis, Pieter R.

doi:10.1016/0005-2736(85)90521-8

Cited by 2,103 publications

(1,257 citation statements)

References 23 publications

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“…Plasmid-cationic lipid complexes were prepared by mixing 500 l plasmid (pCMVLuc, 0.5 mg/ml) in 5% glucose with 500 l DOD-AC:DOPE (1:1) 100 nm diameter LUVs (0.9 mm lipid) prepared by the extrusion method 40 in 5% glucose. This corresponds to a lipid-to-DNA charge ratio (positive-tonegative) of 3.…”

Section: Isolation Of Encapsulated Plasmid By Sucrose Density Gradienmentioning

confidence: 99%

Stabilized plasmid-lipid particles: construction and characterization

et al. 1999

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A detergent dialysis procedure is described which allows of up to 70% and permits inclusion of 'fusigenic' lipids such encapsulation of plasmid DNA within a lipid envelope, as dioleoylphosphatidylethanolamine (DOPE). The in vitro where the resulting particle is stabilized in aqueous media transfection capabilities of SPLP are demonstrated to be by the presence of a poly(ethyleneglycol) (PEG) coating. strongly dependent on the length of the acyl chain conThese 'stabilized plasmid-lipid particles' (SPLP) exhibit an tained in the ceramide group used to anchor the PEG polyaverage size of 70 nm in diameter, contain one plasmid mer to the surface of the SPLP. Shorter acyl chain lengths per particle and fully protect the encapsulated plasmid from result in a PEG coating which can dissociate from the digestion by serum nucleases and E. coli DNase I. Encap-SPLP surface, transforming the SPLP from a stable parsulation is a sensitive function of cationic lipid content, with ticle to a transfection-competent entity. It is suggested that maximum entrapment observed at dioleoyldimethylam-SPLP may have utility as systemic gene delivery systems monium chloride (DODAC) contents of 5 to 10 mol%. The for gene therapy protocols. formulation process results in plasmid-trapping efficiencies

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Section: Isolation Of Encapsulated Plasmid By Sucrose Density Gradienmentioning

confidence: 99%

Stabilized plasmid-lipid particles: construction and characterization

et al. 1999

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“…LUV were prepared by the extrusion method (Hope et al, 1985), using polycarbonate filters with a pore size of 0.1 p m (Nuclepore, Pleasanton, California). For vesicle aggregation or lipid mixing assays, liposomes were routinely prepared in 10 mM HEPES, 200 mM NaCl, pH 7.5 buffer.…”

Section: Preparation Of Liposomesmentioning

confidence: 99%

Interaction of wheat α‐thionin with large unilamellar vesicles

Caaveiro

Molina

Rodrı́guez-Palenzuela

et al. 1998

Protein Science

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The interaction of the wheat antibacterial peptide a-thionin with large unilamellar vesicles has been investigated by means of fluorescence spectroscopy. Binding of the peptide to the vesicles is followed by the release of vesicle contents, vesicle aggregation, and lipid mixing. Vesicle fusion, i.e., mixing of the aqueous contents, was not observed. Peptide binding is governed by electrostatic interactions and shows no cooperativity. The amphipatic nature of wheat a-thionin seems to destabilize the membrane bilayer and trigger the aggregation of the vesicles and lipid mixing. The presence of distearoylphosphatidylethanolamine-poly(ethy1ene glycol 2000) (PEG-PE) within the membrane provides a steric barrier that inhibits vesicle aggregation and lipid mixing but does not prevent leakage. Vesicle leakage through discrete membrane channels is unlikely, because the release of encapsulated large fluorescent dextrans is very similar to that of 8-arninonaphthalene-l,3,6,trisulfonic acid (ANTS). A minimum number of 700 peptide molecules must bind to each vesicle to produce complete leakage, which suggests a mechanism in which the overall destabilization of the membrane is due to the formation of transient pores rather than discrete channels.

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“…Two different preparations of liposomes were obtained, according to Hope et al [7] with minor modifications. An extruder (Lipex Biomembranes, Inc, Vancouver) equipped with two polycarbonate filters of 100 nm pore size (Costar) was used under nitrogen pressure of 25 bars at 40°C.…”

Section: Preparation Of Liposomesmentioning

confidence: 99%

Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes

et al. 1996

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Heparin (HE) exhibited a protective effect on liposome peroxidation induced by Fe 2+ and Cu 2+, decreasing the formation of both conjugated dienes and thiobarbituric acid reactive substances (TBARS) in a dose-dependent manner. The antioxidant activity was more relevant in the oxidizing system employing Fe 2+ and H202 and generating the highly reactive "OH radical. The analysis of liposome size distribution by quasielastic laser light scattering showed that: (1) the native structure of the particles was completely lost after exposure to Fenton reagent; (2) the presence of HE in the reaction mixture completely prevented the peroxidative damage on liposomes. Thus, HE acts as an antioxidant factor on membrane lipid bllayer. This suggests that HE, released from mast-cell granules during inflammatory processes, might locally protect the cell membrane from the oxidative injuries.

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Production of large unilamellar vesicles by a rapid extrusion procedure. Characterization of size distribution, trapped volume and ability to maintain a membrane potential

Cited by 2,103 publications

References 23 publications

Stabilized plasmid-lipid particles: construction and characterization

Stabilized plasmid-lipid particles: construction and characterization

Interaction of wheat α‐thionin with large unilamellar vesicles

Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes

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Production of large unilamellar vesicles by a rapid extrusion procedure. Characterization of size distribution, trapped volume and ability to maintain a membrane potential

Cited by 2,103 publications

References 23 publications

Stabilized plasmid-lipid particles: construction and characterization

Stabilized plasmid-lipid particles: construction and characterization

Interaction of wheat α‐thionin with large unilamellar vesicles

Heparin protection against Fe2+‐and Cu2+‐mediated oxidation of liposomes

Contact Info

Product

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Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes