Effects of ultra-fast nanosecond electric pulses on mitochondria transmembrane potential and oxidation

TL;DR

This study explores how ultra-fast nanosecond electric pulses affect mitochondria and could improve cancer treatment.

Contribution

The paper introduces a new electric pulse generator and shows that ultra-fast nanosecond pulses can lower the threshold for cell membrane permeabilization.

Findings

Nanosecond pulses at ultra-fast repetition frequency reduce cell membrane permeabilization thresholds.

The pulses enable calcium electrochemotherapy at lower electric field amplitudes.

Mitochondrial depolarization and oxidation were observed following the treatment.

Abstract

Electroporation can be successfully employed for controlled molecular delivery and therefore has found clinical applications for treatment of cancer. However, it’s a pulse-dependent phenomenon, thus modulation of the effects is possible by developing new parametric protocols for pulsed electric field generation. In this work, we have developed a generator capable of generating 50 ns pulses with extreme pulse repetition frequency (up to 6.6 MHz), which should enable plasma membrane permeabilization at significantly lower electric field thresholds due to burst compression and modulation of intracellular effects specific to nanosecond range. We have investigated the effects of 6–16 kV/cm, 50 and 300 ns pulses on mitochondria depolarization, followed by ATP depletion study and characterization of mitochondria oxidation. Finally, we have experimentally confirmed the feasibility of the proposed nanosecond pulsed electric field bursts for calcium electrochemotherapy in vitro. For consolidation of knowledge, we have included the results of standard microsecond pulse procedures (8 × 100 µs). As model a CHO-K1-Luc cell line was used. Based on the experimental data, it is concluded that nanosecond pulses (50 ns) when delivered at ultra-fast repetition frequency allow reduction of cell membrane permeabilization thresholds and can be successfully used for calcium electrochemotherapy even with PEF amplitudes as low as 10 kV/cm.

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