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Unilamellar Vesicles

Unilamellar Vesicles are spherical, self-enclosed structures composed of a single lipid bilayer membrane.
These microscopic vesicles serve as models for biological cell membranes and are widely used in biophysical and biochemical research.
Unilamellar Vesicles can be formed through various techniques, such as sonication, extrusion, or detergent removal, and their size, composition, and properties can be tailored for specific applications.
Researchers utilize Unilamellar Vesicles to study membrane dynamics, transport processes, and the interactions between membranes and other biomolecules.
This versetile system offers a controlled environment for investigating fundamental biological processes and developing novel therapeutic approachs.
Explore the latest research and resources on Unilamellar Vesicles to enhance your experimental outcmes and accelerate your discoveries.

Most cited protocols related to «Unilamellar Vesicles»

Experimental datasets used in this study:

Vesicles are giant unilamellar vesicles made of DOPC, supplemented with 0.1% DOPE-Atto647N (ref AD-647N, Atto-tec, Germany) and 0.03% DSPE-PEG(2000) Biotin (ref 880129, Avanti Polar Lipids, USA) electroformed during 1 h at 1V RMS [44 (link)] in a sucrose buffer at 250 milliosmoles. Vesicules were adhered on avidin coated glass coverslips, deflated with an hyperosomotic shock due to buffer evaporation and imaged with a Yokogawa spinning-disc CSU-X1 mounted on a Nikon Ti-Eclipse microscope stand using a 100x objective with NA 1.3 (z spacing 340 nm, xy pixel size 122 nm).

MRI dataset was acquired from a normal healthy person, using a FLAIR sequence.

FIB-SEM 80% confluent HeLa cells were rinsed once with PBS, fixed for 3h on ice using 2.5% glutaraldehyde/2% paraformaldehyde in buffer A (0.15M cacodylate, 2mM CaCl2). Then cells were extensively washed on ice in buffer A, pelleted and incubated 1h on ice in 2% osmium tetroxide and 1.5% potassium Ferro cyanide in buffer A and finally rinsed 5 times in distilled water at room temperature. Cells were then incubated 20min at room temperature in 0.1M thiocarbohydrazide, which had been passed through a 0.22 μm filter, and extensively washed with water. Samples were incubated overnight at 4° C protected from light in 1% uranyl-acetate, washed in water, further incubated in 20mM lead aspartame for 30min at 60°C and finally washed in water. Samples were dehydrated in a graded series ethanol, embedded in hard Epon and incubated for 60h at 45°C then for 60 h at 60°C. A small bloc was cut and mounted on a pin, coated with gold and inserted into the chamber the HELIOS 660 Nanolab DualBeam SEM/FIB microscope (FEI Company, Eindhoven, Netherlands). ROI were prepared using focused ion beam (FIB) and ROI set to be approximatively 20 microns wide. For imaging, electrons were detected using Elstar In-Column secondary electrons Detector (ICD). During acquisition process, the thickness of the FIB slice between each image acquisition was 5 nm.

The drosophila egg chamber is dissected from a drosophila ovary. Cell nuclei were stained with DAPI and cell membranes labeled with the fusion proteins Nrg::GFP and Bsg::GFP [45 (link)]. The egg chamber was embedded in Vectashield and spacers were used to prevent tissue deformation. Images were acquired using an inverted Olympus point scanning confocal microscope IX81 with a 60x objective NA 1.42(z spacing 750 nm, xy pixel size 265 nm).

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Publication 2019
1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 2000) 1,2-oleoylphosphatidylcholine Aspartame Avidin Biotin Buffers Cacodylate Cell Nucleus Cells DAPI Drosophila Electrons EPON Ethanol Focused Ion Beam Scanning Electron Microscopy Gigantism Glutaral Gold HeLa Cells Light Lipids Microscopy Microscopy, Confocal Neuregulins Osmium Tetroxide Ovary paraform Plasma Membrane Potassium Cyanide Shock Sucrose thiocarbohydrazide Tissues Unilamellar Vesicles uranyl acetate
A two-step approach was used to incorporate the connector into the planar bilayer lipid membrane (BLM). The first step was the preparation of unilamellar lipid vesicles containing the reengineered connector as described above. The next step was to fuse the extruded liposome into a planar BLM (Fig. 2i). The fluidity of the lipid bilayer was demonstrated by FRAP (Fluorescence Recovery After Photobleaching) (Fig. 2h). An excitation light was focused continuously on the bilayer to bleach the dye. The photobleached area appeared dark. But after the light was off, it gradually recovered due to the diffusion of the fluorescent lipid.
A standard BLM chamber (BCH-1A from Eastern Sci LLC) was utilized to form horizontal BLMs. A thin Teflon film with an aperture of 70–120 µm (TP-01 from Easter Sci LLC) or 180–250 µm (TP-02 from Easter Sci LLC) in diameter was used as a partition to separate the chamber into cis- (working volume 250 µL) and trans- (working volume 2.5 mL) compartments. After the aperture was pre-painted with 0.5 µL 3% (w/v) DPhPC n-decane solution twice to ensure the complete coating of the entire edge of the aperture, these compartments were filled with conducting buffers (5 mM Tris/pH 7.9, TMS, or 5 mM HEPES/pH 7.9, with varying concentration of NaCl or KCl).
Formation of the bilayer membrane on the partition is a key step for connector insertion into the bilayer (Fig. 2i). Considering all experiments, the occurrence of successful connector insertions was about 47–83%, which varied from person to person based on BLM experience and the quality of prepared proteoliposomes. So far, we have carried out a total of 280 separate BLM experiments in which successful connector insertions were found.
For single conductance measurements, the giant liposome/connector complex prepared earlier must be extruded using a polycarbonate membrane with pore size of 200 nm or 400 nm to generate small unilamellar liposomes. This liposome stock solution was further diluted by 10–20 fold for the BLM experiments before use. For insertion of connectors, 0.5–2 µL of the diluted liposome solution was loaded into the cis-chamber.
Conductance was measured in two ways: the first was derived at specific but constant holding potentials, and the second from the slope of the current trace induced by a scanning potential starting at −100 mV and ramping to 100 mV after incorporation of GP10 connector into the lipid membrane (Fig. 3f and 3g).
Publication 2009
BLM protein, human Buffers decane Diffusion Gigantism HEPES Light Lipid Bilayers Lipids Liposomes Membrane Fluidity polycarbonate proteoliposomes Sodium Chloride Teflon Tissue, Membrane Tromethamine Unilamellar Liposomes Unilamellar Vesicles
Wild type α-syn was expressed and purified as previously described 36 (link),51 (link). The lipids were dissolved in 20 mM phosphate buffer (NaH2PO4/NaH2PO4), pH 6.5, and stirred at 45°C for two hours. The solution was then frozen and thawed 5 times using dry ice and a water bath at 45°C, respectively. The preparation of small or large unilamellar vesicles, SUVs or LUVs, respectively, was done using sonication (3 × 5 min, 50 % cycles, 10 % maximum power) on ice or extrusion through 100 nm pore diameter membranes (Avanti Polar Lipids, Inc) at 45°C, respectively. After centrifugation, the sizes of the SUVs and LUVs were checked using dynamic light scattering (Zetasizer Nano ZSP, Malvern Instruments, Malvern, UK) and show to consist of a distribution centred at 20 and 100 nm diameter, respectively.
Publication 2015
Bath Buffers Centrifugation Dry Ice Freezing Lipids Phosphates Tissue, Membrane Unilamellar Vesicles
A two-step approach was used to incorporate the connector into the planar bilayer lipid membrane (BLM). The first step was the preparation of unilamellar lipid vesicles containing the reengineered connector as described above. The next step was to fuse the extruded liposome into a planar BLM (Fig. 2i). The fluidity of the lipid bilayer was demonstrated by FRAP (Fluorescence Recovery After Photobleaching) (Fig. 2h). An excitation light was focused continuously on the bilayer to bleach the dye. The photobleached area appeared dark. But after the light was off, it gradually recovered due to the diffusion of the fluorescent lipid.
A standard BLM chamber (BCH-1A from Eastern Sci LLC) was utilized to form horizontal BLMs. A thin Teflon film with an aperture of 70–120 µm (TP-01 from Easter Sci LLC) or 180–250 µm (TP-02 from Easter Sci LLC) in diameter was used as a partition to separate the chamber into cis- (working volume 250 µL) and trans- (working volume 2.5 mL) compartments. After the aperture was pre-painted with 0.5 µL 3% (w/v) DPhPC n-decane solution twice to ensure the complete coating of the entire edge of the aperture, these compartments were filled with conducting buffers (5 mM Tris/pH 7.9, TMS, or 5 mM HEPES/pH 7.9, with varying concentration of NaCl or KCl).
Formation of the bilayer membrane on the partition is a key step for connector insertion into the bilayer (Fig. 2i). Considering all experiments, the occurrence of successful connector insertions was about 47–83%, which varied from person to person based on BLM experience and the quality of prepared proteoliposomes. So far, we have carried out a total of 280 separate BLM experiments in which successful connector insertions were found.
For single conductance measurements, the giant liposome/connector complex prepared earlier must be extruded using a polycarbonate membrane with pore size of 200 nm or 400 nm to generate small unilamellar liposomes. This liposome stock solution was further diluted by 10–20 fold for the BLM experiments before use. For insertion of connectors, 0.5–2 µL of the diluted liposome solution was loaded into the cis-chamber.
Conductance was measured in two ways: the first was derived at specific but constant holding potentials, and the second from the slope of the current trace induced by a scanning potential starting at −100 mV and ramping to 100 mV after incorporation of GP10 connector into the lipid membrane (Fig. 3f and 3g).
Publication 2009
BLM protein, human Buffers decane Diffusion Gigantism HEPES Light Lipid Bilayers Lipids Liposomes Membrane Fluidity polycarbonate proteoliposomes Sodium Chloride Teflon Tissue, Membrane Tromethamine Unilamellar Liposomes Unilamellar Vesicles
Small unilamellar vesicles (SUVs) containing a molar ratio of 5:3:2 of DOPE:DOPS:DOPC (Avanti Polar Lipids Inc., USA) were prepared from chloroform solution of the lipid. The lipid mixture was evaporated under a stream nitrogen gas and then dried thoroughly under vacuum, to yield a thin lipid film. Then the dried thin film was re-hydrated adding an aqueous buffer (20 mM sodium phosphate, pH 6.0) and subjected to vortex mixing. Several cycles of freeze-thawing cycles and sonication were carried out until the mixture become clear. In the case of CEST experiments, after sonication, SUVs were mixed with αS samples with a concentration of 0.06% (0.6 mg ml−1). In the case of ssNMR, after sonication, αS was then added to the SUVs mixture up to a molar ratio of 1:65 protein:lipid. Then the mixture was pelleted at 75k (13,500 rpm) for 30 min and 4°C (Beckman Coulter Optima TLX Inc. Brea, USA) by using a rotor TLA 100.3. Subsequently the SUV-αS sample was transferred to 3.2 mm Zirconia XC thin-walled MAS rotor for the SSNMR experiments. POPG SUV-αS samples were prepared using the same protocol but a 50 mM potassium phosphate buffer and 100 mM NaCl at pH 7.4 was used.19 (link)
Publication 2014
1,2-oleoylphosphatidylcholine Buffers Chloroform Droxidopa Freezing Lipids Molar Nitrogen potassium phosphate Proteins Sodium Chloride sodium phosphate Unilamellar Vesicles Vacuum zirconium oxide

Most recents protocols related to «Unilamellar Vesicles»

Vesicles were prepared by the thin-film hydration method as described before34 (link) to obtain a suspension of multilamellar vesicles (MLVs). Large unilamellar vesicles (LUVs) of 100 nm size were obtained by extruding MLVs at least 21 times through two stacked polycarbonate filters and a permeable membrane with 100 nm pores (Nuclepore, Pleasanton, CA, USA). The whole procedure was carried out using an extruder (Avanti Polar Lipids Inc. Alabaster, AL, USA) filled with two 1.0 mL Hamilton syringes (Hamilton, Reno, NV, USA). Vesicles size was confirmed by means of dynamic light scattering (DLS) measurements, which showed a mean hydrodynamic radius consistent with the formation of LUVs. Liposomes with different lipid composition were prepared: POPC/POPG (8/2 mol/mol) and DPPC/POPG (8/2 mol/mol). Liposome samples in the presence of peptides were prepared by mixing appropriate amounts of peptide solution and liposomes suspensions to obtain the required lipid-to-peptide (L/P) ratio. The vesicles containing the fluorescent probe Laurdan were obtained by adding a solution of Laurdan in DMF to the lipid organic mixture at a lipid/Laurdan mole ratio of 30, while vesicles containing the fluorescent probe DPH were obtained by adding a solution of DPH in chloroform to the lipid organic mixture at a lipid/DPH mole ratio of 150.
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Publication 2023
Alabaster Cell Membrane Permeability Chloroform Fluorescent Probes Hydrodynamics laurdan Lipid A Lipids Liposomes Nevus Peptides polycarbonate Radius Syringes Unilamellar Vesicles
Recombinant WT and Q252X human apoA-V were obtained from DNA-protein Technologies LLC in Oklahoma City (www.DNA-Protein.com)31 (link),32 (link) or the laboratory of W. Sean Davidson at the University of Cincinnati33 (link). Proteins were solubilized according to the method described by Castleberry et al.33 (link) into a final buffer of 10mM NH4HCO3 with 5mM DTT, pH7.8. Protein concentration was determined using Pierce Microplate BCA Protein Assay Kit – Reducing Agent Compatible (Thermo Fisher, Waltham, MA).
For HX MS, apoA-V protein was freshly dialyzed from 6M GdnHCl with 10mM DTT into 50mM sodium citrate buffer (pH 3.8) at 4°C before use. Protein concentration was determined by absorbance at 280 nm. Small unilamellar vesicles (SUV, ~20nm diameter) of dimyristoyl phosphatidylcholine (DMPC) (Avanti Polar Lipids, Alabaster AL) at 10mg/ml in aqueous buffer were prepared by sonication34 (link).
Publication Preprint 2023
Alabaster Apolipoprotein A5 Apolipoproteins A Biological Assay Buffers Dimyristoylphosphatidylcholine Homo sapiens HSP40 Heat-Shock Proteins Lipids Proteins Reducing Agents Sodium Citrate Unilamellar Vesicles
The dehydration and rehydration
method79 (link),80 (link) was used to prepare the lipid suspensions.
Briefly, lipids (99 wt %) and lipid-conjugated fluorophores (1 wt
%) were dissolved in chloroform to a final concentration of 10 mg/mL
(cf. Table S1 for a detailed list of lipid
types and membrane compositions). 300 μL of this mixture was
then transferred to a 10 mL round-bottom flask, and the solvent was
removed in a rotary evaporator at reduced pressure (20 kPa) for 6
h to form a dry lipid film. The film was rehydrated with 3 mL of PBS
buffer (5 mM Trizma Base, 30 mM K3PO4, 3 mM
MgSO4·7H2O, 0.5 mM Na2EDTA,
pH 7.4 adjusted with 1 M H3PO4) and stored at
+4 °C overnight to allow the lipid cake to swell. The sample
was then sonicated for 25 s at room temperature, leading to the formation
of multi- and unilamellar giant vesicular compartments. For sample
preparation, 4 μL of the lipid suspension was desiccated for
20 min, and the dry residue was subsequently rehydrated with 0.5 mL
of HEPES-Na buffer containing 10 mM HEPES buffer and 100 mM NaCl,
adjusted to pH 7.8 with 5 M NaOH. The lipid suspension after rehydration
typically contains a few unilamellar vesicles in addition to MLVs
and the hybrid vesicles each comprising a unilamellar vesicle attached
to an MLV. The lipid suspension was thereafter transferred onto a
solid surface submerged in HEPES-Na buffer with addition of 4 mM CaCl2 (pH 7.8 adjusted with 5 M NaOH). The lipid vesicles in the
suspension spontaneously attach to the solid surface.
Publication 2023
Buffers Chloroform Dehydration Gigantism HEPES Hybrids Lipids Pressure Sodium Chloride Solvents Tissue, Membrane Trizma Unilamellar Vesicles
Substrate-loaded unilamellar vesicles were prepared by the thin-film hydration/extrusion method. (i) Typically, a desired amount of the lipid solution in DCM was added to a glass vial and dried under a stream of nitrogen (N2). The residual solvent was then removed under vacuum. The dried lipid film containing 2 mg of lipid was then rehydrated in 1 ml of 2 mM PrPTS in phosphate solution (10 mM, pH 7) and vortexed for 30 s. The resulting solution was extruded 29 times through a polycarbonate membrane with 200-nm pores (nucleopore). The untrapped PrPTS was removed from the LUV suspension by size exclusion chromatography through a Sephadex G-50 column. The LUV solution was diluted to lipid concentration (1 mg/ml), stored in the dark, and used within 12 hours. POPC, POPC/cholesterol, and DMPC LUVs were prepared using the same protocol. (ii) DPPC LUVs were prepared following the above protocol except that hydration and extrusion process was conducted at 50°C (above Tm) and 5% of 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine–poly(ethylene glycol) was added to stabilize LUVs from aggregation.
Publication 2023
Cholesterol Dimyristoylphosphatidylcholine Lipid A Lipids Molecular Sieve Chromatography Nitrogen Nuclear Pore Phosphates Phosphatidylethanolamines Plantar Lipomatosis, Unusual Facies, and Developmental Delay polycarbonate Polyethylene Glycols sephadex G 50 Solvents Tissue, Membrane Unilamellar Vesicles Vacuum
1-palmitoyl,2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), chicken egg yolk sphingomyelin (SM), and cholesterol (Chol) were purchased from Sigma-Aldrich (Darmstadt, Germany). The lipids were mixed in chloroform with desired lipid ratios (Table 1). The lipid films were formed by slowly removing the solvent under a gentle nitrogen stream for 1 h. PBS solution, pH 7.4 (Sigma-Aldrich, Darmstadt, Germany) was added to the lipid films. In order to form lipid vesicles, the lipid films were incubated with PBS at above the melting transition temperature (Tm) for 2 h and intermittently vortexed during incubation. Large unilamellar vesicles (LUVs) of POPC and POPC/Chol vesicles were produced by repeatedly pressing through a polycarbonate membrane 21 times at room temperature with a mini-extruder (Avanti, Birmingham, AL, USA). The sizes of the POPC and POPC/Chol vesicles were approximately 120–130 nm with a polydispersity index (PDI) of about 0.15. The LUVs of the POPC/DPPC, POPC/SM and DOPC/SM vesicles were obtained via tip sonication with a 50% duty cycle for 10 min (Branson sonifier, St. Louis, MO, USA). The sizes of the POPC/DPPC, POPC/SM and DOPC/SM vesicles were approximately 95–105 nm with a PDI of about 0.39. The vesicle sizes were determined via dynamic light scattering with a Zetasizer Nano ZS (Malvern Instrument, Malvern, Worcestershire, UK). The lipid vesicles were kept at temperatures higher than Tm and used within a week.
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Publication 2023
1,2-oleoylphosphatidylcholine 1-palmitoyl-2-oleoylphosphatidylcholine Chickens Chloroform Cholesterol Fever Glycerylphosphorylcholine Lipids Nitrogen Phosphorylcholine polycarbonate Solvents Sphingomyelins Tissue, Membrane Unilamellar Vesicles Yolks, Egg

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1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine is a phospholipid consisting of a glycerol backbone with a palmitic acid and an oleic acid esterified to the first and second carbons, respectively, and a phosphocholine group attached to the third carbon. This compound is a commonly used lipid in various biochemical and biophysical applications.
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1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine is a phospholipid compound that can be used in various laboratory applications. It is a synthetic analog of the naturally occurring phospholipid, phosphatidylserine, which is a key component of biological membranes.
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1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) is a synthetic phospholipid commonly used in research applications. It is a neutral phospholipid composed of a glycerol backbone, two oleic acid chains, and a choline headgroup. DOPC serves as a building block for model lipid membranes and is widely employed in studies involving membrane structure and function.

More about "Unilamellar Vesicles"

Unilamellar vesicles (ULVs) are spherical, self-enclosed structures composed of a single lipid bilayer membrane.
These microscopic vesicles serve as versatile models for biological cell membranes and are widely utilized in biophysical and biochemical research.
ULVs can be formed through various techniques, such as sonication, extrusion, or detergent removal, allowing for the tailoring of their size, composition, and properties to suit specific applications.
Researchers leverage ULVs to investigate fundamental biological processes, including membrane dynamics, transport mechanisms, and the interactions between membranes and other biomolecules.
The controlled environment provided by ULVs offers a valuable platform for studying these phenomena and developing novel therapeutic approaches.
The Avanti Mini-Extruder and LiposoFast are common instruments used to produce ULVs with precise size distributions.
The Zetasizer Nano ZS is a versatile tool for characterizing the size and zeta potential of ULVs, providing insights into their stability and behavior.
Lipids such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) are frequently employed in the formation of ULVs, while 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS) can be incorporated to introduce specific functionalities.
Polycarbonate filters are often used to achieve a narrow size distribution of ULVs.
By exploring the latest research and resources on unilamellar vesicles, researchers can enhance their experimental outcomes and accelerate their discoveries in the field of membrane biology and drug delivery.