Improved detection limits of toxic biochemical species based on impedance measurements in electrochemical biosensors.

An impedance based electrochemical biosensor was designed and fabricated for the detection of various chemical and biological species, with glass as substrate material and gold interdigitated electrodes. A flow cell with inlet and outlet ports for the microfluidic chamber was designed and fabricated using acrylic material with a reservoir volume of 78 μl. The feasibility of the fabricated sensor for detecting very low concentration of chemical and biological species was demonstrated. Electrochemical impedance spectroscopy (EIS) was employed as the detection technique. The impedance based response of the two-terminal device revealed a very high sensitivity with low concentrations of mouse monoclonal IgG, sarcosine, cadmium sulphide (CdS) and potassium chloride (KCl) at pico mole levels.