Electroporation by subnanosecond pulses

Iurii Semenov,Shu Xiao,Andrei G Pakhomov

doi:10.1016/j.bbrep.2016.05.002

Iurii Semenov, Shu Xiao + Show 1 more

Open Access

https://doi.org/10.1016/j.bbrep.2016.05.002

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Abstract

Electropermeabilization of cell membranes by micro- and nanosecond-duration stimuli has been studied extensively, whereas effects of picosecond electric pulses (psEP) remain essentially unexplored. We utilized whole-cell patch clamp and Di-8-ANEPPS voltage-sensitive dye measurements to characterize plasma membrane effects of 500ps stimuli in rat hippocampal neurons (RHN), NG108, and CHO cells. Even a single 500-ps pulse at 190kV/cm increased membrane conductance and depolarized cells. These effects were augmented by applying brief psEP bursts (5–125 pulses), whereas the rate of pulse delivery (8Hz–1kHz) played little role. psEP-treated cells displayed large inward current at negative membrane potentials but modest or no conductance changes at positive potentials. A 1-kHz burst of 25 pulses increased the whole-cell conductance in the range (−100)–(−60)mV to 22–26nS in RHN and NG108 cells (from 3 and 0.7 nS, respectively), but only to 5nS in CHO (from 0.3nS). The conductance increase was reversible within about 2min. Such pattern of cell permeabilization, with characteristic inward rectification and slow recovery, was similar to earlier reported effects of 60- and 600-ns pulses, pointing to the similarity of structural membrane rearrangements in spite of a different membrane charging mechanism.

Highlights

Application of high-voltage electric pulses (EP) of micro- or millisecond duration to living cells is a well-established technique to increase cell membrane permeability and introduce normally impermeable substances into cells [1,2,3]
The current-voltage (I-V) curves measured by a step protocol that was initiated at 1 s after picosecond electric pulses (psEP) delivery were distinguished by a strong increase of inward current at negative transmembrane potentials, but a modest, if any, increase of the outward current at positive potentials
We found that even a single psEP at 190 kV/cm can cause lasting cell membrane permeabilization

Summary

Introduction

Application of high-voltage electric pulses (EP) of micro- or millisecond duration to living cells is a well-established technique to increase cell membrane permeability and introduce normally impermeable substances into cells [1,2,3] This process, termed electroporation or electropermeabilization, has numerous applications in experimental biology, medicine, and biotechnology. Later theoretical and experimental studies established that nsEP cause the formation of long-lived nanopores in the plasma membrane [8,9,10,11]. These nanopores had complex conductive properties, including voltage and current sensitivity, inward rectification, and ion selectivity. The data suggest similar properties of nanopores produced by different treatments, this conjecture has yet to be tested by direct experiments

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