4 May 2012 Impedance biosensor based on interdigitated electrode array for detection of E.coli O157:H7 in food products
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An impedance biosensor was designed, fabricated and tested for detection of viable Escherichia coli O157:H7 in food samples. This device consists of interdigitated microelectrode array (IDEA) fabricated using thin layer of sputtered gold, embedded under a polydimethylsiloxane (PDMS) microchannel. The array of electrodes is designed to detect viable EColi in different food products. The active surface area of the detection array was modified using goat anti-E.coli polyclonal IgG antibody. Contaminated food samples were tested by infusing the supernatant containing bacteria over the IDEA's, through the microchannel. Antibody-antigen binding on the electrodes results in impedance change. Four serial concentrations of E.coli contaminated food samples (3x102 CFUmL-1 to 3x105 CFUmL-1) were tested. The biosensor successfully detected the E.coli samples, with the lower detection limit being 3x103 CFUmL-1 (up to 3cells/μl). Comparing the test results with an IDEA impedance biosensor without microchannel (published elsewhere) indicates that this biosensor have two order of magnitude times higher sensitivity. The proposed biosensor provides qualitative and quantitative detection, and potentially could be used for detection of other type of bacteria by immobilizing the specific type of antibody.
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Shibajyoti Ghosh Dastider, Shibajyoti Ghosh Dastider, Syed Barizuddin, Syed Barizuddin, Majed Dweik, Majed Dweik, Mahmoud F. Almasri, Mahmoud F. Almasri, } "Impedance biosensor based on interdigitated electrode array for detection of E.coli O157:H7 in food products", Proc. SPIE 8369, Sensing for Agriculture and Food Quality and Safety IV, 83690Q (4 May 2012); doi: 10.1117/12.920821; https://doi.org/10.1117/12.920821

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