A three-electrode electrochemical biosensor has been developed using printed circuit boards for detecting bacterial contamination. This low-cost, small-size device consists of thin-film gold electrodes and is fabricated using photo-lithography paired with electro-deposition. Pathogen presence is deduced by detection of change in electrical impedance caused by binding of the pathogen to bio-receptors coated on the sensor surface. The biosensor has a total area of ~3.2 cm2 and requires only 100 µL of test sample for detection. The sensor geometry has been optimized using techniques from Design of Experiments, and the device can be operated using a small ac excitation potential of magnitude 5 mV. The sensor is tested on the common food-borne pathogen Salmonella typhimurium and is able detect bacterial concentrations of the order of 500 CFU/mL within 6 min. In this paper, the design and fabrication of the biosensor is detailed along with the experiments that validate its performance.

Original languageEnglish (US)
Pages (from-to)210-216
Number of pages7
JournalIEEE Sensors Journal
Issue number1
StatePublished - 2011


  • Biomedical transducers
  • design automation
  • electrochemical processes
  • impedance measurement

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering

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