Smart chip for visual detection of bacteria using the electrochromic properties of polyaniline
Ranjbar, Saba (Institut Català de Nanociència i Nanotecnologia)
Nejad, Mohammad Amin Farahmand (Institut Català de Nanociència i Nanotecnologia)
Parolo, Claudio (Institut Català de Nanociència i Nanotecnologia)
Shahrokhian, Saeed (Sharif University of Technology. Department of Chemistry)
Merkoçi, Arben (Institut Català de Nanociència i Nanotecnologia)

Date:	2019
Abstract:	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 readout for the visual detection of Escherichia coli. Electropolymerizing polyaniline (PANI) on an 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 (taking advantage of the many amine groups of PANI). 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 4 orders of magnitude with a limit of detection of 10 colony forming unit per 1 mL (CFU mL) by the naked eye and 10 CFU mL using ImageJ software. In this work we show that merging the sensitivity of electrochemistry with the user-friendliness of an optical readout can generate a new and powerful class of biosensors, with potentially unlimited applications in a variety of fields.
Grants:	European Commission 795635 Ministerio de Economía y Competitividad SEV-2017-0706 Ministerio de Economía y Competitividad MAT2017-87202-P
Note:	Altres ajuts: the ICN2 is funded by the CERCA Programme/Generalitat de Catalunya.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Colony forming units ; Electrochemical signals ; Electrochromic behavior ; Electrochromic properties ; Measure concentration ; Pathogenic bacterium ; Public health issues ; Screen printed electrodes
Published in:	Analytical chemistry, Vol. 91, issue 23 (Dec. 2019) , p. 14960-14966, ISSN 1520-6882

DOI: 10.1021/acs.analchem.9b03407

Postprint 8 p, 1.2 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles