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Journal of Sensors
Volume 2011, Article ID 190284, 7 pages
http://dx.doi.org/10.1155/2011/190284
Research Article

Smart Integrated Sensor for Multiple Detections of Glucose and L-Lactate Using On-Chip Electrochemical System

1Department of Electronic and Information Engineering, Toyohashi University of Technology, C3-601, 1-1 Hibarigaoka, Tenpaku, Toyohashi, Aichi, 441-8580, Japan
2New Product Development Department, Hioki E. E. Corporation, 81 Koizumi, Ueda, Nagano 386-1192, Japan
3JST-CREST, Sanban-cho Building, 4F, 5 Sanban-cho, Chiyoda-ku, Tokyo 102-0075, Japan

Received 14 February 2011; Accepted 26 April 2011

Academic Editor: Michele Penza

Copyright © 2011 Tomoyuki Yamazaki 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

Multiple sensor electrodes, a supplementary electrode, a reference electrode, and signal-processing circuits were integrated on a single chip to develop a chip-shaped electrochemical sensing system. L-lactate and glucose were measured using on-chip working electrodes modified by polyion complex to immobilize lactate oxidase and glucose oxidase, respectively. Cyclic voltammetry measurements were conducted using an on-chip potentiostat. Selective and quantitative detection of glucose and L-lactate and the interference behavior were studied. Hydrogen peroxide generated by enzymatic reactions was detected by an increase in anodic oxidation current. Reaction currents at +0.7 V versus Ag/AgCl were used to obtain calibration plots. The measured dynamic ranges for L-lactate and glucose were 0.2–1.0 mM and 2.0–8.0 mM, respectively. The sensitivities were 65 nA/mM and 15 nA/mM, respectively, using a working electrode of 0.5 mm2. The 3σ detection limit was 0.19 mM and 1.1 mM, respectively. We have achieved multiple biomaterial detections on a circuit-equipped single chip. This integrated electrochemical sensor chip could be the best candidate for realizing point-of-care testing due to its portability and potential for mass production.