Phase separation of miscible phospholipids by sonication of bilayer vesicles

Bakouche, Ouahid; Gerlier, Denis; Létoffé, J. M.; Claudy, P.

doi:10.1016/s0006-3495(86)83432-4

Cited by 14 publications

(8 citation statements)

References 15 publications

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“…GCSAa-DMPE liposomes were unable to act as primary or secondary immunogens when used in combined experiments with the powerful GCSAa-DSPC liposome immunogen. Those two immunogens were also found to be unsuitable as tertiary stimulators of fully immune spleen cells harvested from rats immunized with two injections of GCSAa-DSPC liposomes and adoptively transferred to naive recipients ( Table 2) whereas, as previously reported [20], the GCSAa-DSPC liposomes were strong immunogens. The incorporation of a soluble antigen into liposomes has been found to increase its immunogenicity by avoiding the generation of a radiosensitive immunosuppressive mechanism*.…”

Section: Resultssupporting

confidence: 61%

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Impairment of immunogenicity by antigen presentation in liposomes made from dimyristoylphosphatidyl‐ethanolamine linked to the secretion of prostaglandins by macrophages

1987

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The induction of antibody response in syngeneic rats by the Gross virus cell surface antigen (GCSAa) was dependent on the presentation of GCSAa into liposomes made from distearoylphosphatidylcholine (DSPC). GCSAa liposomes made from dimyristoylphosphatidylethanolamine (DMPE) were nonimmunogenic, even when used as anamnestic immunogens. Spleen cells, from rats twice immunized with GCSAa-DSPC-liposomes and used to transfer the anti-GCSAa immune response into naive recipients after a tertiary immunostimulation in vitro in the presence of naive peritoneal exudate cells (PEC), responded to soluble GCSAa only after irradiation at 500 rds and to GCSAa-DMPE-liposomes only when indomethacin was added during the in vitro stimulation. The preincubation of these cells with empty DMPE liposomes or the addition of supernatant from PEC fed with DMPE liposomes abrogated the response to GCSAa-DSPC liposomes. Using a specific radioimmunoassay, prostaglandin E2 was demonstrated to be produced by PEC when fed with DMPE liposomes, and not when fed with DSPC liposomes. This prostaglandin E2 secretion by PEC induced by DMPE liposomes was inhibited by indomethacin.

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Section: Resultssupporting

confidence: 61%

“…The adoptive transfer experiments were performed as recently described [20]. Briefly, the spleens were collected 3 weeks after the second immunization from rats immunized with GCSAa-DSPC liposomes.…”

Section: Immunizations and Adoptive Transfermentioning

confidence: 99%

Impairment of immunogenicity by antigen presentation in liposomes made from dimyristoylphosphatidyl‐ethanolamine linked to the secretion of prostaglandins by macrophages

1987

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“…The lipids were allowed to self‐assemble in the presence of Martini water starting from a complete random configuration of all the molecules. The simulations were performed with an isothermal–isobaric ensemble (NPT) at a temperature of 323 K, which is above the chain‐melting temperature (∼315 K) of the DPPC lipids . The CG model allows a larger time step than that of traditional atomistic simulations.…”

Section: Methodsmentioning

confidence: 99%

“…The simulations were performed with an isothermal-isobaric ensemble (NPT) at at emperature of 323 K, which is above the chain-meltingt emperature( 315 K) of the DPPC lipids. [57,58] The CG model allows al arger time step than that of traditional atomistic simulations. In our case, we used at ime step of 15 fs.…”

Section: Self-assembly Of Lipidsmentioning

confidence: 99%

Free Energy of Bare and Capped Gold Nanoparticles Permeating through a Lipid Bilayer

Mhashal

Roy

2016

ChemPhysChem

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Herein, we study the permeation free energy of bare and octane-thiol-capped gold nanoparticles (AuNPs) translocating through a lipid membrane. To investigate this, we have pulled the bare and capped AuNPs from bulk water to the membrane interior and estimated the free energy cost. The adsorption of the bare AuNP on the bilayer surface is energetically favorable but further loading inside it requires energy. However, the estimated free-energy barrier for loading the capped AuNP into the lipid membrane is much higher compared to bare AuNP. We also demonstrate the details of the permeation process of bare and capped AuNPs. Bare AuNP induces the curvature in the lipid membrane whereas capped AuNP creates an opening in the interacting monolayer and get inserted into the membrane. The insertion of capped AuNP induces a partial unzipping of the lipid bilayer, which results in the ordering of the local lipids interacting with the nanoparticle. However, bare AuNP disrupts the lipid membrane by pushing the lipid molecules inside the membrane. We also analyze pore formation due to the insertion of capped AuNP into the membrane, which results in water molecules penetrating the hydrophobic region.

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“…All samples were prepared by 10 cycles of successive sonication at 303 K (30 min) and cooling at 278 K. D 2 O was used as a solvent in preparation of the DMPC/surfactant mixture for better visualization of the carbonyl region in the FTIR spectroscopy [20]. Sonication at a temperature higher than the phase transition point prevents phase separation [21] and allows better incorporation of the surfactant molecules into phospholipids bilayers [22].…”

Section: Sample Preparationmentioning

confidence: 99%