Effect of Cell Size and Shape on Electric Field Threshold and Critical Transmembrane Voltage for Electroporation

Abstract

Introduction: Electroporation is a technique for increasing the permeability of the cell membrane to <br/>otherwise non-permeate molecules due to an external electric field. This permeability enhancement is <br/>detectable if the induced transmembrane voltage becomes greater than a critical value which depends on the <br/>pulse strength threshold. In this study, the variability of the electric field threshold and the minimal <br/>transmembrane voltage resulting in detectable electroporation of the plasma membrane of spherical and <br/>irregularly shaped cells have been investigated. <br/>Materials and Methods: Spherical cells of different dimensions and attached cells of various shapes were <br/>selected. The chosen cells were exposed to 100 0s electric pulses with incrementing amplitudes. <br/>Electroporation was detected by an increase in the fluorescence caused by an influx of Ca 2+ and the threshold <br/>electric field for each cell was recorded. A 3D geometrical model of each cell was constructed from its cross <br/>sectional images. Simulation using the finite element method was performed to obtain the critical induced <br/>transmembrane voltage for each individual cell. <br/>Results: The magnitudes of the electric field strength threshold and critical transmembrane voltage versus <br/>cell radius were obtained for spherical cells. To investigate the effects of cell shapes and orientations on the <br/>field strength threshold and critical voltage, the considered attached cells were categorized into three different <br/>groups. Field strength threshold and critical voltage was obtained for each cells and the results for the <br/>different groups were compared. <br/>Discussion and Conclusion: Size, shape and orientation of cells affect the critical transmembrane voltage <br/>and all these elements in turn influence the electric field threshold and, therefore, the efficiency of <br/>electroporation.