Finite element modelling of non-faradic electric impedance spectroscopy through flexible polymer microchip

Abstract

Numerical simulations using finite element method were performed for a better understanding of nonfaradic electric impedance response of microfluidic device with two insulated planar-microband electrodes i.e. electrodes without direct contact with electrolyte flowing in the microchannel. The results showed that calculated electric impedance depends not only on the microchannel geometry and dielectric properties of electrolyte flowing in microchannel, but also on the dielectric response of the insulated PET layer. It was pointed out that a microfluidic device with insulated microelectrodes behaves as a dielectric device, in which a strong capacitive coupling effect takes place in the high-frequency domain. An analytical expression that allows predicting the optimal frequency range to be used for measuring real-time contactless microchannel resistance changes was proposed. This non-faradic impedance spectroscopy appears to be a promising approach for the new generation of sensors and biosensors in miniaturized flexible or patch polymer devices.