An RC-Model for Dielectrophoresis of Ellipsoidal Cells: A Method for Determnination of Dielectric Properties

This work proposes an RC-model representing an ellipsoidal cell being induced in an AC electric field. The frequency dependent complex function of the induced cell dipole moment is expressed in terms of real and imaginary parts, which explains cell dielectric properties. This approach provides a simpler method so that only three values are required from experimentation. There are two critical frequencies at the lower (f_clscr) and the higher (f_ch ) boundary which determine cross over points from negative to positive DEP force exerting on the cell and vice versa. By increasing the solution conductivity (sigma_s), these frequencies converge and join as soon as the sigma_s, reaches a critical value(sigma_ct). Under this critical conductivity the cell experiences a zero force, and the conductivity of the cytoplasm (sigma_c) can be predicted. This work reveals permittivity and conductivity of the membrane and the cytoplasm of yeasts.