Electrical impedance analysis of cell growth using a parallel RC circuit model

For label-free and real-time monitoring of cells during growth, the electrical impedance of cell-covered electrodes was measured and analysed by an equivalent parallel-RC circuit model. The impedance of a cell-layer model was simulated in the frequency range of 100 Hz to 1 MHz at different cell sizes and cell-cell gaps by using finite element method to understand how morphological changes of cells affect the impedance of the cell-layer. The simulated impedance of the cell-layer could be represented by a parallel-connected capacitance and resistance at frequencies below 10 kHz but not at frequencies higher than 10 kHz. The capacitance and resistance of the celllayer were dependent on cell size and cell-cell gap. The impedance analysis of cells with the equivalent RC circuit model was proper to characterize the extracellular information and to estimate changes in cell size and cell-cell gap.