Computer simulation for electrochemical impedance of a living cell adhered on the inter-digitated electrode sensors

The sensitivity of inter-digitated electrode (IDE) impedance sensors for adherent cell monitoring is investigated by computer simulation. Governing equation based on Maxwell's equation is solved using finite element method by a commercially-available software to obtain impedance with/without living cells on sensor surface. For IDE, the current concentration is shown to be higher along the edges, as a result of which the electrode edges have a higher impact on impedance. The higher sensitivity is observed in case of higher cell density and larger cell size due to larger occupancy on sensor surface. It is also seen that the smaller electrode geometry displays higher sensitivity in the presence of adherent cell comparable or smaller than electrode spacing. This behavior is explained in view of the increase in number of electrode edges. It is also found out that the sensitivity of IDE outperforms to that of facing electrode (FE) for adherent cell sensing owing to the larger cell coverage and higher current concentration along the electrode edges. It is important to note that the IDE shows higher sensitivity than the FE in the presence of adherent cell, which is in contrast to the previously reported sensitivity behavior for floating cell. This makes IDE as a suitable choice of electrode for experimentalists working on adherent cell studies.