New multispecific array as a tool for electrochemical impedance spectroscopy-based biosensing.

Using electrochemical impedance spectroscopy (EIS) for biosensing applications typically requires repetitive experiments. To address this need, we have designed a multispecific electrochemical array with eight individually addressable 2mm-diameter gold working electrodes for rapid biosensing data accumulation by EIS in the presence of redox agent. The array allows to incorporate multiple negative controls in the course of a single binding experiment, as well as to perform parallel identical experiments to improve reliability of detection. The array is fit with attached electrochemical cell with Ag/AgCl mini reference electrode and can be used to process macro samples of 0.5-1 ml or micro samples of 5 microl in a drop-wise fashion. Eight individual EIS measurements are completed in 15 min. The reported array is disposable, economical and is easy to use. Examples of array use for label-free genetic sensing of 2.7 kb-long target Yersinia pestis DNA and for protein sensing of Ricin Toxin Chain A (RTA) are presented. We suggest the reported array design as a tool for researchers in the area of EIS sensing. Copyright 2009 Elsevier B.V. All rights reserved.