Elsevier

Available online 2 July 2021, 107882

Bioelectrochemistry

Highlights

Nanosecond pulses can electroporate cells without stimulating them.

This may be explained by a minimum time

tmin

required for channel opening.

We derive the electrostimulation threshold for channels with such a

tmin

.

The safety factor says how far above stimulation electroporation occurs.

The safety factor drops sharply for low membrane time constant and pulse duration.

Abstract

While electrical stimulation with pulses of milli- or microsecond duration is possible without electroporation, stimulation with nanosecond pulses typically entails electroporation, and nanosecond pulses can even cause electroporation without stimulation. A recently proposed explanation for this intriguing finding is that stimulation requires not only that a threshold membrane potential is reached, but also that it is sustained for a certain time

tmin

, while electroporation occurs almost immediately after a higher threshold potential is reached. Here we analytically derive stimulation and electroporation thresholds for membranes that satisfy these assumptions. We analyze the safety factor, i.e. the ratio between electroporation and stimulation threshold and its dependence on pulse duration, membrane charging time constant, and

tmin

. We find that the safety factor is sharply reduced if both the pulse duration and the membrane charging time constant are below

tmin

. We discuss different approaches to get models with varying

tmin

that could be used to experimentally test this theory and cardiac applications.

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© 2021 Published by Elsevier B.V.



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