Two-dimensional nanosecond electric field mapping based on cell electropermeabilization

Meng-Tse Chen,Martin A Gundersen,P Thomas Vernier,Yu-Hsuan Wu,Chunqi Jiang

doi:10.1186/1757-5036-2-9

Meng-Tse Chen, Martin A Gundersen + Show 3 more

Open Access

https://doi.org/10.1186/1757-5036-2-9

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Journal: PMC Biophysics	Publication Date: Nov 11, 2009
Citations: 47	License type: CC BY 2.0

Affiliation: University of Southern California

Abstract

Nanosecond, megavolt-per-meter electric pulses cause permeabilization of cells to small molecules, programmed cell death (apoptosis) in tumor cells, and are under evaluation as a treatment for skin cancer. We use nanoelectroporation and fluorescence imaging to construct two-dimensional maps of the electric field associated with delivery of 15 ns, 10 kV pulses to monolayers of the human prostate cancer cell line PC3 from three different electrode configurations: single-needle, five-needle, and flat-cut coaxial cable. Influx of the normally impermeant fluorescent dye YO-PRO-1 serves as a sensitive indicator of membrane permeabilization. The level of fluorescence emission after pulse exposure is proportional to the applied electric field strength. Spatial electric field distributions were compared in a plane normal to the center axis and 15-20 μm from the tip of the center electrode. Measurement results agree well with models for the three electrode arrangements evaluated in this study. This live-cell method for measuring a nanosecond pulsed electric field distribution provides an operationally meaningful calibration of electrode designs for biological applications and permits visualization of the relative sensitivities of different cell types to nanoelectropulse stimulation. PACS Codes: 87.85.M-

Highlights

Ultra-short (< 100 ns), high-field (MV/m) electric pulses produce a variety of effects [1], including release of intracellular calcium [2,3], eosinophil disruption [4], vacuole permeabilization [5], mitochondrial release of cytochrome c [6], caspase activation [7,8], and phosphatidylserine (PS) externalization [9,10]
Nanosecond electric pulses have been shown to kill a wide variety of human cancer cells in vitro, including basal cell carcinoma and pancreatic cancer cells, and to induce tumor regression in vivo [11,12], and nanoelectropulse therapy is under development for
3.1 Nanoelectropulse-induced membrane permeabilization depends on pulse amplitude It has been reported that cellular permeabilization in Jurkat T lymphoblasts with ultra-short (< 10 ns), high-field (MV/m) electric pulses is a function of pulse count [17]

Summary

Introduction

Ultra-short (< 100 ns), high-field (MV/m) electric pulses produce a variety of effects [1], including release of intracellular calcium [2,3], eosinophil disruption [4], vacuole permeabilization [5], mitochondrial release of cytochrome c [6], caspase activation [7,8], and phosphatidylserine (PS) externalization [9,10]. In the present work we demonstrate, using live cell responses, a qualitative mapping of the electric field around three electrode configurations, and we show the correspondence of these electric field profiles with those expected from electromagnetic modeling. Extension of this method can lead to a better and more rigorously quantitative analysis of electric field distributions around electrodes in biological systems, leading to an increased understanding of the in vivo electroporation process and contributing to evaluations of the efficacy of nanoelectropulse exposure in clinical applications

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Conclusion