Dielectric dispersion in biological cells of complex geometry simulated by the three-dimensional finite difference method

This paper describes numerical simulations of dielectric dispersion in biological cells of complex geometry to which analytical approaches are not applicable. A numerical technique based on the three-dimensional finite difference method (3D-FDM) has been developed to calculate the equivalent complex permittivity of a system including a single cell or periodically arranged cells in a continuous medium. It has been tested with a spherical cell model, whose equivalent complex permittivity is calculated from analytical formulae. The agreement between the dielectric spectra calculated by 3D-FDM and from the analytical formulae was quite satisfactory with volume fractions of cells up to 0.5. Furthermore, dielectric spectra were simulated for cells in cell division, i.e. a spherical cell divides into two spherical cells via a doublet-shaped cell with a narrow cytoplasmic junction.