A Multiwalled‐Carbon‐Nanotube‐Based Biosensor for Monitoring Microcystin‐LR in Sources of Drinking Water Supplies |
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| Authors: | Changseok Han Amos Doepke Wondong Cho Vlassis Likodimos Armah A de la Cruz Tyson Back William R Heineman H Brian Halsall Vesselin N Shanov Mark J Schulz Polycarpos Falaras Dionysios D Dionysiou |
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| Affiliation: | 1. Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221‐0012, USA;2. Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221‐0172, USA;3. Chemical Engineering, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221‐0012, USA;4. Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems (IAMPPNM), Division of Physical Chemistry, NCSR Demokritos, 15310 Aghia Paraskevi Attikis, Athens, Greece;5. US EPA, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH 45268, USA;6. Air Force Research Laboratory, Materials and Manufacturing Directorate, Electronic and Optical Materials Branch (AFRL/RXPS), Wright‐Patterson AFB, OH 45433‐7077, USA;7. Universal Technology Corporation, 1270 N. Fairfield Rd, Dayton, OH 45432, USA;8. Mechanical Engineering and Mechanical Engineering Technology, School of Dynamic System, University of Cincinnati, Cincinnati, OH 45221‐0072, USA;9. Nireas‐International Water Research Centre, University of Cyprus, 20537 Nicosia, Cyprus |
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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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| Keywords: | biosensors carbon nanotubes cyanotoxins drinking water microcystin‐LR |
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