Electrochromic Immunosensor: Smart Chip for Visual Detection of Bacteria
Paper ID : 1038-ICNS
Saba Ranjbar *1, Mohammad Amin Farahmand Nejad2, Claudio Parolo3, Saeed Shahrokhian4, Arben Merkoci3
1Department of Chemistry, Sharif University of Technology, Tehran 11155-9516, Iran
2Department of Chemistry, Sharif University of Technology, ‎Tehran 11155-9516, Iran‎
3Nanobioelectronics and Biosensor Group, Catalan Institute ‎of Nanoscience and Nanotechnology (ICN2), CSIC, ‎The ‎Barcelona Institute of Science and Technology, Campus ‎UAB, Bellaterra, 08193, Barcelona, Spain
4Department of Chemistry, Sharif University of Technology, Tehran 11155-9516, Iran‎ Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, Iran
Finding fast and reliable ways to detect pathogenic bacteria is crucial for addressing serious ‎public ‎health issues in ‎clinical, environmental and food settings. Here, we present a novel ‎assay based on the ‎conversion of an ‎electrochemical signal into a more convenient optical read ‎out for the visual detection ‎of E. Coli. Electropolymerizing ‎polyaniline (PANI) on indium tin ‎oxide screen-printed electrode (ITO ‎SPE), we achieved not only the desired ‎electrochromic ‎behavior but also a convenient way to modify ‎the electrode surface with antibodies. Applying ‎a ‎constant potential to the PANI-‎modified ITO SPE induces a change in their oxidation state, which in ‎turn generates a ‎color change on the electrode surface. The ‎presence of E. Coli on the electrode surface ‎increases the resistance in the ‎circuit affecting the PANI oxidation states, ‎producing a different ‎electrochromic response. Using this electrochromic ‎sensor, we could ‎measure concentrations of E. Coli ‎spanning four orders of magnitude with a limit of detection ‎of ‎‎102 ‎‎(CFU mL-1). In this work, we show that merging ‎the sensitivity of electrochemistry with ‎the user-friendliness of an ‎optical read out can generate a new ‎and powerful class of ‎biosensors, with potentially unlimited applications in a ‎variety of fields. ‎
Electrochromic immuonosensor; Polyaniline; Multicolour electrochromic behaviour; E. Coli ‎O157:H7‎; Visual ‎detection.‎
Status : Abstract Accepted (Oral Presentation)