Engineering Commons^™

Control Of The Electroporation Efficiency Of Nanosecond Pulses By Swinging The Electric Field Vector Direction, Vitalii Kim, Iurii Semenov, Allen S. Kiester, Mark A. Keppler, Bennett L. Ibey, Joel N. Bixler, Ruben M. L. Colunga Biancatelli, Andrei G. Pakhomov

Bioelectrics Publications

Reversing the pulse polarity, i.e., changing the electric field direction by 180°, inhibits electroporation and electrostimulation by nanosecond electric pulses (nsEPs). This feature, known as “bipolar cancellation,” enables selective remote targeting with nsEPs and reduces the neuromuscular side effects of ablation therapies. We analyzed the biophysical mechanisms and measured how cancellation weakens and is replaced by facilitation when nsEPs are applied from different directions at angles from 0 to 180°. Monolayers of endothelial cells were electroporated by a train of five pulses (600 ns) or five paired pulses (600 + 600 ns) applied at 1 Hz or 833 kHz. Reversing …

Pulsed Electric Field Ablation Of Esophageal Malignancies And Mitigating Damage To Smooth Muscle: An In Vitro Study, Emily Gudvangen, Uma Mangalanathan, Iurii Semenov, Allen S. Kiester, Mark A. Keppler, Bennett L. Ibey, Joel N. Bixler, Andrei G. Pakhomov

Bioelectrics Publications

Cancer ablation therapies aim to be efficient while minimizing damage to healthy tissues. Nanosecond pulsed electric field (nsPEF) is a promising ablation modality because of its selectivity against certain cell types and reduced neuromuscular effects. We compared cell killing efficiency by PEF (100 pulses, 200 ns–10 µs duration, 10 Hz) in a panel of human esophageal cells (normal and pre-malignant epithelial and smooth muscle). Normal epithelial cells were less sensitive than the pre-malignant ones to unipolar PEF (15–20% higher LD50, p < 0.05). Smooth muscle cells (SMC) oriented randomly in the electric field were more sensitive, with 30–40% lower LD50 (p < 0.01). Trains of ten, 300-ns pulses at 10 kV/cm caused twofold weaker electroporative uptake of YO-PRO-1 dye in normal epithelial cells than in either pre-malignant cells or in SMC oriented perpendicularly to the field. Aligning SMC with the field reduced the dye uptake fourfold, along with a twofold reduction in Ca²⁺ transients. A 300-ns pulse induced a twofold smaller transmembrane potential in cells aligned with the field, making them …

Atmospheric Air Plasma Streamers Deliver Nanosecond Pulses For Focused Electroporation, Shu Xiao, Carol Zhou, Eric Appia, Shirshak Dhali

Bioelectrics Publications

Background: For electrotherapies that involve electrodes and high-intensity electric fields, such as in tissue ablation, we report a method of pulse delivery that can focus the electric field away from the electrodes, as demonstrated in vitro.

Materials and Methods: To electroporate cells in a monolayer seeded in a 35 mm culture dish, two atmospheric-pressure plasma channels generated by two thin, copper foil electrodes above the surface of the solution provided the current and established the electric field.

Results: Depending on the pulse duration, the plasma channels were observed as corona (100 ns), streamer (300 ns), and mixture of streamer …