A Multiwalled-Carbon-Nanotube-Based Biosensor for Monitoring Microcystin-LR in Sources of Drinking Water Supplies

Authors

  • Changseok Han,

    1. Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA
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  • Amos Doepke,

    1. Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, USA
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  • Wondong Cho,

    1. Chemical Engineering, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA
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  • Vlassis Likodimos,

    1. Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems (IAMPPNM), Division of Physical Chemistry, NCSR Demokritos, 15310 Aghia Paraskevi Attikis, Athens, Greece
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  • Armah A. de la Cruz,

    1. US EPA, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH 45268, USA
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  • Tyson Back,

    1. Air Force Research Laboratory, Materials and Manufacturing Directorate, Electronic and Optical Materials Branch (AFRL/RXPS), Wright-Patterson AFB, OH 45433-7077, USA
    2. Universal Technology Corporation, 1270 N. Fairfield Rd, Dayton, OH 45432, USA
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  • William R. Heineman,

    1. Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, USA
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  • H. Brian Halsall,

    1. Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, USA
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  • Vesselin N. Shanov,

    1. Chemical Engineering, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA
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  • Mark J. Schulz,

    1. Mechanical Engineering and Mechanical Engineering Technology, School of Dynamic System, University of Cincinnati, Cincinnati, OH 45221-0072, USA
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  • Polycarpos Falaras,

    1. Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems (IAMPPNM), Division of Physical Chemistry, NCSR Demokritos, 15310 Aghia Paraskevi Attikis, Athens, Greece
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  • Dionysios D. Dionysiou

    Corresponding author
    1. Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA
    2. Nireas-International Water Research Centre, University of Cyprus, 20537 Nicosia, Cyprus
    • Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA.
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Abstract

A multiwalled carbon nanotube (MWCNT)-based electrochemical biosensor is developed for monitoring microcystin-LR (MC-LR), a toxic cyanobacterial toxin, in sources of drinking water supplies. The biosensor electrodes are fabricated using vertically well-aligned, dense, millimeter-long MWCNT arrays with a narrow size distribution, grown on patterned Si substrates by water-assisted chemical vapor deposition. High temperature thermal treatment (2500 °C) in an Ar atmosphere is used to enhance the crystallinity of the pristine materials, followed by electrochemical functionalization in alkaline solution to produce oxygen-containing functional groups on the MWCNT surface, thus providing the anchoring sites for linking molecules that allow the immobilization of MC-LR onto the MWCNT array electrodes. Addition of the monoclonal antibodies specific to MC-LR in the incubation solutions offers the required sensor specificity for toxin detection. The performance of the MWCNT array biosensor is evaluated using micro-Raman spectroscopy, including polarized Raman measurements, X-ray photoelectron spectroscopy, cyclic voltammetry, optical microscopy, and Faradaic electrochemical impedance spectroscopy. A linear dependence of the electron-transfer resistance on the MC-LR concentration is observed in the range of 0.05 to 20 μg L−1, which enables cyanotoxin monitoring well below the World Health Organization (WHO) provisional concentration limit of 1 μg L−1 for MC-LR in drinking water.

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