Formation of Giant Vesicles from

Fischer, Aline, Formation of Giant Vesicles from Different Kinds of Lipids Using the Electrothermal Method, 6, 37 see also Oberholzer, Thomas, 6, 285. 

Formation of Giant Vesicles from Different Kinds of Lipids using the Electroformation Method... 

In the literature the formation of giant vesicles from PS [9e] is described, but our studies indicated that giant vesicles do not form firom pure PS, at least under the conditions of 10 Hz and 8 V, using bovine brain PS. 

Figure 9 Formation of giant vesicles by fusion of LUVs equipped with an amphiphilic dipyridine ligand and filled with rhodamine sulfonate (50 xM) in presence of NiCL (0.1 xM) observed by fluorescence microscopy. The time between the first panel (upper left) and the last one (lower right) was 7 s. Scale bar 10 pm. (Reproduced with permission from Ref. 61. National Academy of Sciences, 2004.)...

Whilst the solvent-free and solvent-displacement methods yield polymersomes with diameters ranging from nanometers up to a few micrometers, giant vesicles of tens of micrometers in diameter can be formed by electroformation or copolymer stabilized double emulsions methods. Electroformation of giant vesicles is triggered by an a.c. field that is applied across an amphiphilic polymer film to enhance water diffusion and film hydration. The double emulsion method consists on the formation of a leaflet of the inner membrane using one copolymer type as a stabilizer for a... 

These questions also have a chemical component it would be helpful to understand the relationship between the chemical structure of the monomeric surfactant and the propensity to assemble to giant vesicles. It has been observed that, generally, a small amount of giant vesicles accompanies the formation of normal vesicles. However, this tendency varies strongly from surfactant to surfactant. This situation also occurs in the case of electroformation [2] some surfactants (e.g. fatty acids/soaps, phosphatidyl nucleosides) fail to give giant vesicles by the electro-formation method [3], and in fact the method seems to be restricted to phosphatidylcholine or to lipid mixtures containing phosphatidylcholine. It is fair to say that the relationship between the chemical structure and the propensity to form vesicles is still poorly understood. 

The electroformation method is used in a number of laboratories for studies involving individual GUVs. In comparison with earlier methods for the preparation of giant vesicles, electroformation has advantages, leading to the formation of giant unilamellar vesicles from a variety of lipids. 

Koster G, VanDuijn M, Hofs B, Dogterom M (2003) Membrane tube formation from giant vesicles by dynamic association of motor proteins. Proc. Natl. Acad. Sci. USA 100 15583-15588. 

Fig. 15 Top-, formation of a giant amphiphile from a synthetic polymer reconstituted with a heme cofactor and horse radish peroxididase (HRB). Bottom-, transmission electron micrographs of PEO113- -PS48 micelles (left) and PEO113- -PS48-HRP vesicles (right) formed in water. Reprinted with permission from [60], copyright (2007) American Chemical Society...

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