Resonance-Like Impedance Measurement Technique for Life Science Applications

In this article, we propose a novel real-time method to convert standard impedance spectroscopy of an N-shaped negative differential resistance (NDR) system into resonance-like pseudo-impedance spectroscopy. This method relies on the creation of a singularity in the impedance spectra with the frequency, where the real and imaginary parts of the impedance are equal to zero and pure capacitive, respectively. This resonance-like impedance spectrum allows us to monitor a unique frequency related to the electrochemical events at the interface between electrode and sample. The proposed method was validated using an NDR created by an indium tin oxide (ITO) microelectrode array exposed to mouse neuroblastoma cells with two different concentrations 1 x 10(4) and 2 x 10(4) cells/mL. Based on the results and discussions in this article, resonance-like impedance spectroscopy offers advantages for the rapid detection and real-time monitoring of biological and/or chemical NDR systems.