Many approaches for studying the transmembrane potential (TMP) induced during the treatment of biological cells with pulsed electric fields have been reported. From the simple analytical models to more complex numerical models requiring significant computational resources, a gamut of methods have been used to recapitulate multicellular environments in silico. Cells have been modeled as simple shapes in two dimensions as well as more complex geometries attempting to replicate realistic cell shapes. In this study, we describe a method for extracting realistic cell morphologies from fluorescence microscopy images to generate the piecewise continuous mesh used to develop a finite element model in two dimensions. The preelectroporation TMP induced in tightly packed cells is analyzed for two sets of pulse parameters inspired by clinical irreversible electroporation treatments. We show that high-frequency bipolar pulse trains are better, and more homogeneously raise the TMP of tightly packed cells to a simulated electroporation threshold than conventional irreversible electroporation pulse trains, at the expense of larger applied potentials. Our results demonstrate the viability of our method and emphasize the importance of considering multicellular effects in the numerical models used for studying the response of biological tissues exposed to electric fields.

Predictions of the electrostatic force (EF) for charged conducting spheres have been made previously using first-principles electrostatics [J. Lekner, Meas. Sci. Technol. 23, 085007 (2012)]. Here, finite element calculations of EF are presented for a variety of conducting ellipsoids differing with respect to size, gap distance, orientation, and shape. The results are expressed in terms of directly measurable experimental parameters. Our results are consistent with those of Lekner, namely, that charged ellipsoids exhibit mutual repulsion at all distances when they have the same charging potential, otherwise EF becomes attractive when the gap distance between the two ellipsoids is close enough. Additionally, we analyze the relationship between short-range attraction, capacitance, and EF in detail. The complexity of the electrostatic response on both external and material parameters suggests applications not only in electrostatics but in plasmonics and biosensor devices as well.

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