Development of a Printed Impedance Based Electrochemical Sensor for E. Coli Detection

A printed impedance based electrochemical sensor was successfully developed on a flexible substrate for detection of Escherichia coli, a common pathogen that causes wound infections. This flexible sensor was fabricated by screen printing silver/silver chloride (Ag/AgCI) ink as working and reference electrodes on polyimide (Kapton) substrate. The capability of the fabricated electrochemical sensor for detecting trace concentrations of E. coli in defibrinated sheep's blood was investigated. The electrochemical impedance spectroscopy (EIS) based response of the printed sensor revealed detection levels as low as
$10^{3}$
colony forming units (CFU)/mL as well as the capability of the sensor to distinguish among varying levels
$(10^{3},10^{5},10^{7}\text{CFU}/\text{mL})$
of sample. The EIS response of the developed electrochemical sensor has been analyzed and is presented in this paper.