In this study, our laboratory used a separative structure of extended gate
field effect transistor (EGFET) to detect pH value and constructed an enzym
e modified field effect transistor (EnFET) by coupling them with a membrane
containing immobilized acetylcholinesterase (AcChE). The enzyme-catalyzed
hydrolysis reaction of acetylcholine seemed to be resulted in the pH change
of the membrane due to the formation of acetic acid. This structure has a
lot of advantages, such as being insensitive toward light, being simple to
in its passivation and package, and the flexibility of shape in the extende
d gate area, etc. In addition, it is easier to fabricate and package the se
nsors, and the measurement is simple for the application of disposable bios
ensor. (C) 2000 Elsevier Science B.V. All rights reserved.