Membrane properties of giant polymer and lipid vesicles obtained by electroformation and pva gel-assisted hydration methods

Dao, Thi Phuong Tuyen; Fauquignon, Martin; Fernandes, Fábio; Ibarboure, Emmanuel; Vax, Amélie; Prieto, Manuel; Meins, Jean-François Le

doi:10.1016/j.colsurfa.2017.09.005

Cited by 39 publications

(71 citation statements)

References 44 publications

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“…Most methods report sinusoidal alternating currents of lower voltages for lipids (1–3 V) and higher ones for polymer (9–10 V). Nevertheless, lower voltages similar to lipids have been reported for polymers, or liposomes at voltage up to 5–6 V independently of ITO/Pt electrodes. Dimova et al was able to prove that lowering the voltage to 800 mV also generated polymersome GUVs but required longer times to form, 3 h, contrary to 15 min at 9 V .…”

Section: Methodsmentioning

confidence: 91%

“…For polymers, concentrations of ≥4 mg mL −1 are regularly used which is not surprising as polymers have a higher molar masses molecular weight than lipids. In addition, lower values (1 mg mL −1 ) similar to liposomes have also been reported . Surprisingly, the mass concentration of polymers is not correlated to the polymer molecular weight M n even though polymers significantly vary in their degrees of polymerization.…”

Section: Methodsmentioning

confidence: 97%

“…Besides the setup, the conditions can vary between different studies without any obvious reasons ( Table 1 ). In terms of frequency, regardless of ITO/Pt electrodes or lipid/polymer amphiphiles, most studies uses 10 Hz, which is sometimes followed by a decrease of the frequency to 4–5 Hz, said to be required for GUV detachment . Some experiments also use frequencies as low as 1 Hz or as high as 500 Hz for lipids .…”

Section: Methodsmentioning

confidence: 99%

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Self‐Assembly of Giant Unilamellar Vesicles by Film Hydration Methodologies

2019

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Self‐assembly of lipids or polymeric amphiphiles into vesicular structures has been achieved by various methods since the first generation of liposomes in the 1960s. Vesicles can be obtained with diameters from the nanometer to the micrometer regime. From the perspective of cell mimicking, vesicles with diameters of several micrometers are most relevant. These vesicles are called giant unilamellar vesicles (GUVs). Commonly used methods to form GUVs are solvent‐displacement techniques, especially since the development of microfluidics. These methodologies however, trap undesirable organic solvents in their membrane as well as other potentially undesired additives (surfactants, polyelectrolytes, polymers, etc.). In contrast to those strategies, summarized herein are solvent‐free approaches as suitable clean alternatives. The vesicles are formed from a dry thin layer of the lipid or amphiphilic polymers and are hydrated in aqueous media using the entropically favored self‐assembly of amphiphiles into GUVs. The rearrangement of the amphiphilic films into vesicular structures is usually aided by shear forces such as an alternative current (electroformation) or the swelling of water‐soluble polymeric supports (gel‐assisted hydration).

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Section: Methodsmentioning

confidence: 91%

Section: Methodsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

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Self‐Assembly of Giant Unilamellar Vesicles by Film Hydration Methodologies

2019

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“…[12,21,22]). Approaches based on vesicle swelling on polymer films [23,24] were not employed because they result in polymer residues encapsulated in the vesicles and maybe even in the membrane [25,26], which is more pronounced at high temperature. Methods based on transfer of lipids from an oil phase to an aqueous one [27,28] were also avoided because of the inherent risk of remaining oil residues in the bilayer, which may influence the membrane phase behavior.…”

Section: Vesicle Stability Is Reduced Upon Fast Cooling After Preparamentioning

confidence: 99%

Micron-sized domains in quasi single-component giant vesicles

Knorr

Steinkühler

Dimova

2018

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Giant unilamellar vesicles (GUVs), are a convenient tool to study membrane-bound processes using optical microscopy. An increasing number of studies highlights the potential of these model membranes when addressing questions in membrane biophysics and cell-biology. Among them, phase transitions and domain formation, dynamics and stability in raft-like mixtures are probably some of the most intensively investigated. In doing so, many research teams rely on standard protocols for GUV preparation and handling involving the use of sugar solutions. Here, we demonstrate that following such a standard approach can lead to the abnormal formation of micron-sized domains in GUVs grown from only a single phospholipid. The membrane heterogeneity is visualized by means of a small fraction (0.1 mol%) of a fluorescent lipid dye. For dipalmitoylphosphatidylcholine GUVs, different types of membrane heterogeneities were detected. First, the unexpected formation of micron-sized dye-depleted domains was observed upon cooling. These domains nucleated about 10 K above the lipid main phase transition temperature, T. In addition, upon further cooling of the GUVs down to the immediate vicinity of T, stripe-like dye-enriched structures around the domains are detected. The micron-sized domains in quasi single-component GUVs were observed also when using two other lipids. Whereas the stripe structures are related to the phase transition of the lipid, the dye-excluding domains seem to be caused by traces of impurities present in the glucose. Supplementing glucose solutions with nm-sized liposomes at millimolar lipid concentration suppresses the formation of the micron-sized domains, presumably by providing competitive binding of the impurities to the liposome membrane in excess. It is likely that such traces of impurities can significantly alter lipid phase diagrams and cause differences among reported ones.

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“…We present here different methods by which MVLs may be produced, namely electroformation on indium tin oxide (ITO) coated glass. Electroformation is a common method for producing standard, single compartment giant liposomes [31,32,33,34,35,36,37,38,39], also known as 'giant unilamellar vesicles', but has not, to our knowledge, been described as a viable method for producing MVLs. The benefits of this approach are twofold: 1.…”

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confidence: 99%

Towards experimental P-systems using multivesicular liposomes

2019

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P-systems are abstract computational models inspired by the phospholipid bilayer membranes generated by biological cells. Illustrated here is a mechanism by which recursive liposome structures (multivesicular liposomes) may be experimentally produced through electroformation of dipalmitoylphosphatidylcholine (DOPC) films for use in 'real' P-systems. We first present the electroformation protocol and microscopic characterisation of incident liposomes towards estimating the size of computing elements, level of internal compartment recursion, fault tolerance and stability. Following, we demonstrate multiple routes towards embedding symbols, namely modification of swelling solutions, passive diffusion and microinjection. Finally, we discuss how computing devices based on P-systems can be produced and their current limitations. A P-system or 'membrane computer' is an abstract computational model inspired by biological reactions occurring within the confines of phospholipid (PL) membrane-encapsulated living cells and their subcomponents. Briefly, P-systems are envisaged as hypothetical recursive membrane-bound compartments wherein internal symbolic objects, likened to chemicals and catalysts, may react with each other to do computation, the products of which may remain within their compartment or diffuse inwards or outwards through their

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Membrane properties of giant polymer and lipid vesicles obtained by electroformation and pva gel-assisted hydration methods

Cited by 39 publications

References 44 publications

Self‐Assembly of Giant Unilamellar Vesicles by Film Hydration Methodologies

Self‐Assembly of Giant Unilamellar Vesicles by Film Hydration Methodologies

Micron-sized domains in quasi single-component giant vesicles

Towards experimental P-systems using multivesicular liposomes

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