Limits...
Metastable pores at the onset of constant-current electroporation.

Kotulska M, Basalyga J, Derylo MB, Sadowski P - J. Membr. Biol. (2010)

Bottom Line: During this stage two species of metastable pores open, the majority of very low conductance that seem not fully developed as hydrophilic electropores.Membrane capacitance has a great impact on the membrane susceptibility to the pore appearance, related to its thickness and integrity.Pores of nonperfect membranes appear more easily, but they do not live any longer than others.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, ul. Wybrzeze Wyspianskiego 27, 50-370, Wroclaw, Poland. malgorzata.kotulska@pwr.wroc.pl

ABSTRACT
Single metastable nanopores, appearing before the actual electroporation under constant-current conditions, are used to characterize the onset of electroporation. Unlike the long-lived electropores typical of the current controlled methods, these pores survive for milliseconds and observing them is possible due to slow development of electroporation, provided by the gradual accumulation of charges on a planar membrane. Analysis of the metastable pore appearance frequency and lifetime shows the first introductory stage of electroporation. During this stage two species of metastable pores open, the majority of very low conductance that seem not fully developed as hydrophilic electropores. The experiments reveal that voltage value defines the electroporation onset while the current value affects the rate of electroporation. Membrane capacitance has a great impact on the membrane susceptibility to the pore appearance, related to its thickness and integrity. Pores of nonperfect membranes appear more easily, but they do not live any longer than others.

Show MeSH
Frequency of prepore appearance very weakly depends on the current value
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2914259&req=5

Fig4: Frequency of prepore appearance very weakly depends on the current value

Mentions: The PC planar bilayer membrane was subjected to constant current of a value close to the lower limit capable of inducing electroporation, which exceeds the current leaks and ensures the slowest electroporation (from our experience it is above 0.15 nA). In several cases metastable pores were developed. We could observe them above 0.18 nA, with the maximum appearance frequency at 0.22 nA and a decrease above this value, with no metastable pores observed at 0.24–0.25 nA (Fig. 4). This result defines the optimal current range for studying the onset of electroporation. The experiment shows that metastable pore appearance does not depend on the current value for very low currents (the maximum at 0.22 nA was caused by a higher ratio of pores with high conductance, presented below). At higher currents, we did not observe metastable pores at our sampling frequency but the electroporation proceeded faster and the pores may have appeared and disappeared undetected.Fig. 4


Metastable pores at the onset of constant-current electroporation.

Kotulska M, Basalyga J, Derylo MB, Sadowski P - J. Membr. Biol. (2010)

Frequency of prepore appearance very weakly depends on the current value
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2914259&req=5

Fig4: Frequency of prepore appearance very weakly depends on the current value
Mentions: The PC planar bilayer membrane was subjected to constant current of a value close to the lower limit capable of inducing electroporation, which exceeds the current leaks and ensures the slowest electroporation (from our experience it is above 0.15 nA). In several cases metastable pores were developed. We could observe them above 0.18 nA, with the maximum appearance frequency at 0.22 nA and a decrease above this value, with no metastable pores observed at 0.24–0.25 nA (Fig. 4). This result defines the optimal current range for studying the onset of electroporation. The experiment shows that metastable pore appearance does not depend on the current value for very low currents (the maximum at 0.22 nA was caused by a higher ratio of pores with high conductance, presented below). At higher currents, we did not observe metastable pores at our sampling frequency but the electroporation proceeded faster and the pores may have appeared and disappeared undetected.Fig. 4

Bottom Line: During this stage two species of metastable pores open, the majority of very low conductance that seem not fully developed as hydrophilic electropores.Membrane capacitance has a great impact on the membrane susceptibility to the pore appearance, related to its thickness and integrity.Pores of nonperfect membranes appear more easily, but they do not live any longer than others.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, ul. Wybrzeze Wyspianskiego 27, 50-370, Wroclaw, Poland. malgorzata.kotulska@pwr.wroc.pl

ABSTRACT
Single metastable nanopores, appearing before the actual electroporation under constant-current conditions, are used to characterize the onset of electroporation. Unlike the long-lived electropores typical of the current controlled methods, these pores survive for milliseconds and observing them is possible due to slow development of electroporation, provided by the gradual accumulation of charges on a planar membrane. Analysis of the metastable pore appearance frequency and lifetime shows the first introductory stage of electroporation. During this stage two species of metastable pores open, the majority of very low conductance that seem not fully developed as hydrophilic electropores. The experiments reveal that voltage value defines the electroporation onset while the current value affects the rate of electroporation. Membrane capacitance has a great impact on the membrane susceptibility to the pore appearance, related to its thickness and integrity. Pores of nonperfect membranes appear more easily, but they do not live any longer than others.

Show MeSH