Randles Circuit Analysis Toward Investigating Interfacial Effects on Microchannel Electrodes

Electrochemical impedance spectroscopy, coupled with the employment of microchannels having specific geometric designs, has been shown as a viable methodology for characterizing biological cells in a noninvasive and label-free manner. In this article, we investigate the modulation of the interfacial impedance characteristics of such a system when an electrolyte solution is introduced with the presence and absence of biologic analogs. The systems are studied through the use of simulation and equivalent circuit modeling. Devices were fabricated with and without microchannels in order to evaluate the effects of electric field confinement and demonstrate the significance of geometric design of the microchannel on the measured impedance signals of the system, characterized at the electrode/microchannel interface. These devices were then tested using cell media as the electrolyte solution. Three solutions were used, one without the biologic analog, and solutions of low and high concentrations of the analog.