Synthesis Method and High Salt Concentration Can Affect Electrodeformation of GUVs under Strong Pulsed DC Fields

The study focuses on two important issues in the electrodeformation of giant unilamellar vesicles (GUVs) as biomimic objects, with regard to their electroporation. The results are presented with respect to the ratio of the conductivities of the inner and outer fluids of the GUV, (β = Λ_en/Λ_sus), and the concentration of salt in the enclosed medium (C _en). In this work, low and high salt concentration regimes are referred to as C _en ≤ 0.3 mM and C _en ≥ 25 mM respectively. First, responses of GUVs under strong pulsed DC fields are observed to be sensitive to the synthesis methods (electroporation or gel-assisted method) for both β = 1 and β < 1 in the low salt concentration regime. This might be caused by a higher initial membrane tension (in the case of electroformed GUVs) or possibly a greater membrane edge tension (in the case of GUVs prepared by the gel-assisted method). Second, the effect of salt concentration on the electrohydrodynamic behavior of GUVs under strong pulsed DC fields indicates that the extent of poration and pore growth and, correspondingly, the shape deformation can be qualitatively different at different salt concentrations. This suggests the possibility of higher edge tension in GUVs as well as faster "electrical shorting" of the membrane due to the abundance of ions and thereby lower pore growth in high-salt GUVs. The study shows that the extrapolation of results obtained in GUV electroporation to biological cells should be done with caution.