Non-faradaic electrochemical impedance spectroscopy analysis of C-MEMS derived bio-modified glassy carbon electrode

Abstract

In this work, we have developed a carbon-microelectromechanical systems derived glassy carbon electrode (GCE) for non-faradaic electrochemical impedance spectroscopy (nf-EIS) measurement to detect electrode interfacial changes upon biomodification. This is carried out using a three-electrode system configuration. The fabricated electrode was electrochemically characterized in phosphate-buffered solution, and then changes in impedance were observed upon bio-modification of the electrode surface. The absence of any labelling molecule and no redox indicators makes the measurement system more straightforward and precise. The investigations were done using a standard deoxyribonucleic acid (DNA) immobilization on the GCE. The surface modification was done using a two-step assembly protocol linking the probe to the carbon electrode and blocking the unwanted sites using a spacer chemical-mercaptohexanol. The results obtained help us to understand the electrical signatures upon bio-modification of electrodes in the presence of a probe and its complementary 50 ng μl−1 DNA target. nf-EIS relies on various microscopic interactions, which occur at the electrode–electrolyte interface system. We are currently working on extending this study to develop a precise, accurate and sensitive sensor to detect bio-molecular interactions occurring on the GCE to detect disease-causing microorganisms in contaminated water samples.