Bursting of charged multicomponent vesicles subjected to electric pulses

Strong electric pulses applied to phosphatidylcholine (PC) giant vesicles induce the formation of pores, which reseal within milliseconds. Here, we study the response of vesicles containing PC and negatively charged lipids like phospatidylglycerol (PG) to such pulses. Vesicles composed of 1:1 PG:PC in a buffered solution of Hepes and EDTA exhibit the same behaviour as observed with PC membranes. Surprisingly, when the medium is changed to a non-buffered solution with or without salt, the vesicles burst and disintegrate to tubular structures after the pulse is applied. A fast digital camera and confocal microscopy were used to observe the dynamics of vesicle rupture and the membrane reorganization after the applied pulse. The nature of this instability and structural rearrangement is poorly understood. The experiments reported here suggest that the membrane charge plays a significant role. Vesicles made of lipid extract from human plasma membranes behave in the same fashion, implying that the reported bilayer reorganization may also occur to a certain degree in the membrane of electroporated cells.