Biomimetic giant vesicles electroformation: biophysical evidences

Giant Unilamellar Vesicles (GUV) are liposomes of 10-100 μm of diameter formed by a single phospholipid bilayer encompassing an aqueous core. Their cell-like size motivates the wide use of GUV as model membrane system, with the advantage to be visible under light microscope. The most commonly used method of GUV preparation is the so called “electroswelling” of lipids under Alternating Current electric field which leads to a homogeneous population of spherical vesicles characterized by a narrow size distribution. Despite their great relevance as biomimetic system, the underlying mechanism of GUV formation is still poorly understood and an univocal model explaining the vesicles formation is still lacking. In this work, by using phase contrast microscopy we have performed a real time study on the kinetic of GUV growth. At the same time, we have characterized the structural and topological properties of electroformed vesicles through fluorescence and confocal microscopy, with the final aim to define a simple and intuitive model which connects the vesicles features with the electric field parameters, namely frequency, voltage and waveform.