Plasma membrane permeabilization by trains of ultrashort electric pulses.
Ultrashort electric pulses (USEP) cause long-lasting increase of cell membrane electrical conductance, and that a single USEP increased cell membrane electrical conductance proportionally to the absorbed dose (AD) with a threshold of about 10 mJ/g. The present study extends quantification of the membrane permeabilization effect to multiple USEP and employed a more accurate protocol that identified USEP effect as the difference between post- and pre-exposure conductance values (Deltag) in individual cells. We showed that Deltag can be increased by either increasing the number of pulses at a constant E-field, or by increasing the E-field at a constant number of pulses. For 60-ns pulses, an E-field threshold of 6 kV/cm for a single pulse was lowered to less than 1.7 kV/cm by applying 100-pulse or longer trains. However, the reduction of the E-field threshold was only achieved at the expense of a higher AD compared to a single pulse exposure. Furthermore, the effect of multiple pulses was not fully determined by AD, suggesting that cells permeabilized by the first pulse(s) in the train become less vulnerable to subsequent pulses. This explanation was corroborated by a model that treated multiple-pulse exposures as a series of single-pulse exposures and assumed an exponential decline of cell susceptibility to USEP as Deltag increased after each pulse during the course of the train.
Ibey
Bennett L
BL
Radio Frequency Radiation Branch, 711th Human Performance Wing, Air Force Research Laboratory, Brooks City Base, San Antonio, TX, United States.
Mixon
Dustin G
DG
Payne
Jason A
JA
Bowman
Angela
A
Sickendick
Karl
K
Wilmink
Gerald J
GJ
Roach
W Patrick
WP
Pakhomov
Andrei G
AG
D000818:Animals; D002460:Cell Line; D002463:Cell Membrane Permeability; D004560:Electricity; D055724:Electrophysiological Phenomena; D057054:Molecular Imaging; D051381:Rats; D013997:Time Factors