Publication details

Authors: Han, C.; Doepke, A.; Cho, W.; Likodimos, V.; de la Cruz, A. A.; Back, T.; Heineman, W. R.; Halsall, H. B.; Shanov, V. N.; Schulz, M. J.; Falaras, P.; Dionysiou, D. D. 
Title: A Multiwalled-Carbon-Nanotube-Based Biosensor for Monitoring Microcystin-LR in Sources of Drinking Water Supplies 
Type: Journal Article 
Publisher: Advanced Functional Materials 
Year: 2013 
Volume: 23 
Issue: 14 
Start Page: 1807 
End Page: 1816 
DOI: 10.1002/adfm.201201920 
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 degrees 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 g L1, which enables cyanotoxin monitoring well below the World Health Organization (WHO) provisional concentration limit of 1 g L1 for MC-LR in drinking water. 
Keywords: biosensors, carbon nanotubes, cyanotoxins, drinking water, microcystin-lr, electrochemical impedance spectroscopy, rapid detection, liquid-chromatography, raman-spectroscopy, inhibition assay, cyanobacteria, electrodes, supercapacitors, graphitization, purification 
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