Four Electrode EIS Measurement on Interdigitated Microelectrodes for Adherent Cell Growing and Differentiation Monitoring

Protocols employed in cell and tissue engineering usually involve destructive tests to characterize the cell cultures, mainly in the case of adherent cells. Impedance spectroscopy obtained with planar electrodes is an alternative to perform non-destructive, on-line measurements. The antecedents of this technique use the two-electrode strategy, then providing high sensitivity but also a high dependence on the electrode coverage. In order to improve the accuracy and to separate cell density from coverage and adhesion we use a four electrode-strategy with interdigitated microelectrodes. The preliminary results have been previously reported. In this communication a set of results obtained with animal cell cultures are presented. The measurement set-up consists of miniature bioreactors (10 ml) where a double set of interdigitated microelectrodes (AbTech) has been inserted. They are connected to an impedance analyser through a custom front-end. The set is placed in an incubator together with parallel cultures in order to provide control cell counting along the 7 days cell growing. The four-electrode follow-up method provides higher sensitivity (63%) than the two-electrodes method, showing this last one a reduced response mainly near the culture end.