Microfabricated On-Line Sensor for Continuous Monitoring of L -Glutamate

• Published in: Analytical Sciences 1998, Vol.14(5), pp.947-953
• Main Authors: NIWA, Osamu, HORIUCHI, Tsutomu, KURITA, Ryoji, TABEI, Hisao, TORIMITSU, Keiichi
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensors; Biotechnology; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Various methods and equipments
• ISSN: 0910-6340; 1348-2246
• DOI: 10.2116/analsci.14.947

An on-line sensor was developed by using a micro-machining technique for the continuous measurement of extracellular glutamate. The sensor was made by bonding two glass plates together. One of the plates has a rectangular flow channel which is connected to both a sampling and an outlet capillary. The other has a carbon film-based electrochemical cell, which consists of an enzyme-modified electrode surrounded by polymer film to form a thin-layer-channel flow cell. The sensor has a high analyte conversion efficiency due to the cell structure. As a result, we obtained a low detection limit of 44 nM (S/N=3). The cathodic current started to increase about 10 s after sample introduction at a flow rate of 2 μl/min due to its small inner volume. Using the sensor, we can monitor the extracellular L -glutamate increase caused by stimulating it with KCl and γ-aminobutyric acid (GABA) by locating the sampling capillary very close to the cell.