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Advances in Materials Science and Engineering
Volume 2014 (2014), Article ID 971942, 12 pages
http://dx.doi.org/10.1155/2014/971942
Research Article

Bienzymatic Acetylcholinesterase and Choline Oxidase Immobilized Biosensor Based on a Phenyl Carboxylic Acid-Grafted Multiwalled Carbon Nanotube

1Department of Chemistry, Hannam University, Daejeon 305-811, Republic of Korea
2RedoxTech, 198-24 Myeonmok-dong, Jungnang-gu, Seoul 131-823, Republic of Korea

Received 2 January 2014; Accepted 6 February 2014; Published 13 March 2014

Academic Editor: Yong Chae Jung

Copyright © 2014 So-Ra Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Bienzymatic acetylcholinesterase (AChE) and choline oxidase (ChOx) immobilized biosensor based on a phenyl carboxylic acid-grafted multiwalled carbon nanotube (MWNT) modified glass carbon electrode (GCE) and carbon-screen printed electrode (SPE) was fabricated for acetylcholine detection in human blood samples. Phenyl carboxylic acid-modified MWNT supports were prepared by electrochemical polymerization of 4-carboxyphenyl diazonium salts, which were synthesized by an amine group and sodium nitrite, on the surface of the MWNT-modified GCE and SPE in 0.1 M PBS. The successful fabrication of the AChE-ChOx-immobilized biosensor was confirmed via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The sensing range of the biosensor based on a GCE and SPE was 1.0~10 μM and 10~100 μM, respectively. The interfering effect of 0.1 M L-ascorbic acid, 0.1 M L-cysteine, and 0.1 M uric acid to 0.1 M acetylcholine was 3.00%, 9.00%, and 3.00%, respectively. Acetylcholine in a human blood sample was detected by the AChE-ChOx-immobilized biosensor.