A Detailed Model for High-Frequency Impedance Characterization of Ovarian Cancer Epithelial Cell Layer Using ECIS Electrodes

We report on the electrical impedance spectroscopy characterization of OVCA429 ovarian cancer cells. A commercially available eight-well cell culture impedance array (ECIS-8W1E), commonly used in electrical cell-substrate impedance sensing (ECIS), was used for OVCA429 characterization. Impedances of ECIS-8W1E array were recorded with cell culture medium (without cells) and with OVCA429 cell layer in the culture medium between 100 Hz and 10 MHz frequency. Physiological and interfacial components of experimental impedance data were modeled by equivalent circuit fitting, using a newly developed model. Impedance measurements with cell culture medium show only two semicircles in the admittance plane, which are identified as: 1) low-frequency semicircle due to impedance of gold electrode in contact with the electrolyte and 2) high-frequency semicircle due to impedance of polymer-coated region of the gold electrode in contact with the electrolyte. In the presence of OVCA429 cell layer, three convolved semicircles are observed in the Cole-Cole plane, which are identified as the interfacial impedance in series with the cell layer impedance. The average resistance and capacitance of the OVCA429 cell layer was found to be 152 +/- 59 Omega . cm(2) and 8.5 +/- 2.4 mu F/cm(2), respectively.