Development of a High-Sensitivity Printed Impedance Based Electrochemical Sensor for Detecting E. Coli

In this study, a flexible substrate was used to develop a flexible printed impedance-based electrochemical sensor for the detection of wound bacteria. Escherichia coli was detected since it is a common pathogen causing wound infection. The electrochemical sensor was fabricated by screen printing silver/silver chloride (Ag/AgCl) ink in a dentated spiral structure onto a polyimide (Kapton) substrate as working/reference electrodes, respectively. The electrochemical sensor was evaluated for its capability to detect extremely low concentrations of E. coli in defibrinated sheep's blood. The electrochemical impedance spectroscopy (EIS) analysis of the printed sensor demonstrated its capability to detect E. coli at detection levels as low as 10
²
colony forming units (CFU)/mL. Additionally, the sensor exhibited the capability to distinguish various levels of E. coli in the concentration range from 10
²
to 10
⁷
CFU/mL.