Electroformation of giant unilamellar vesicles from large liposomes

Abstract

Giant unilamellar vesicles (GUVs) are widely used as model systems for biological membranes to study membrane-related processes in a precisely controlled in vitro environment, owing to their biophysical properties. The classical technique for the formation of giant liposomes starts with the dissolution of lipids or lipid mixtures in an organic solvent, which is then deposited as a thin lipid solution film on a support substrate. In this study, we present a comprehensive analysis investigating the effect of different lipid compositions on the generation of GUVs from preformed liposomes under non-ionic and ionic conditions. For all liposome types tested, the electroformation process, whether performed on indium tin oxide-coated glass slides or platinum wires, consistently produced GUVs that typically ranged in size from 5 to 20 μm. However, the yield of GUVs varied depending on the specific non-ionic or ionic conditions and the lipid composition of the preformed liposomes used. In general, the resulting population of giant vesicles was predominantly characterised by the presence of unilamellar and multivesicular vesicles. These findings have the potential to improve the refinement of protocol parameters for the formation of GUVs containing membrane proteins and for the study of the effects of lipid composition on membrane protein activity.