title: Size of the pores created by an electric pulse: microsecond vs millisecond pulses.
abstract: Here, the sizes of the pores created by square-wave electric pulses with the duration of 100 μs and 2 ms are compared for pulses with the amplitudes close to the threshold of electroporation. Experiments were carried out with three types of cells: mouse hepatoma MH-22A cells, Chinese hamster ovary (CHO) cells, and human erythrocytes. In the case of a short pulse (square-wave with the duration of 100 μs or exponential with the time constant of 22 μs), in the large portion (30-60%) of electroporated (permeable to potassium ions) cells, an electric pulse created only the pores, which were smaller than the molecule of bleomycin (molecular mass of 1450 Da, r≈0.8 nm) or sucrose (molecular mass of 342.3 Da, radius-0.44-0.52 nm). In the case of a long 2-ms duration pulse, in almost all cells, which were electroporated, there were the pores larger than the molecules of bleomycin and/or sucrose. Kinetics of pore resealing depended on the pulse duration and was faster after the shorter pulse. After a short 100-μs duration pulse, the disappearance of the pores permeable to bleomycin was completed after 6-7 min at 24-26°C, while after a long 2-ms duration pulse, this process was slower and lasted 15-20 min. Thus, it can be concluded that a short 100-μs duration pulse created smaller pores than the longer 2-ms duration pulse. This could be attributed to the time inadequacy for pores to grow and expand during the pulse, in the case of short pulses.
authors: Laboratory of Biophysics for Bionanotechnology and Medicine, Department of Biology, Faculty of Natural Sciences, Vytautas Magnus University, 58 K. Donelaicio str., Kaunas, LT-44248, Lithuania. g.saulis@gmf.vdu.lt
authors: Gintautas
authors: G
authors: Saulis
authors: Rita
authors: R
authors: Saulė
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000494:pharmacology; D016466:CHO Cells; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000648:ultrastructure*; D002463:Cell Membrane Permeability; D006224:Cricetinae; D004560:Electricity; D018274:Electroporation; D004910:Erythrocyte Membrane / Q000648:ultrastructure*; D004912:Erythrocytes / Q000187:drug effects / Q000648:ultrastructure*; D006801:Humans; D051379:Mice; D013395:Sucrose / Q000494:pharmacology
chemical_list: D001761:Bleomycin; D013395:Sucrose