Enhancement of the Stability of Wired Quinoprotein Glucose Dehydrogenase Electrode

Abstract

Quinotrotein glucose dehydrogenase (EC1.1.99.17) was electrically wired to a glassy carbon electrode with an osmiun complex containing redox polymer. The current output of the electrode reached 1.8 mA cm-2 at 70 mM glucose and it was insensitive to oxygen and nearly insensitive to pH change in 6.3 to 8.3 pH range. The half life of the electrode was about 8 hours. The main cause of the current decay was the leaching of the enzyme from the redox polymer/enzyme film. The stability of the electrode was improved by increasing the extent of the crosslinking of the film and/or overcoating the electrode. The overcoated electrodes had typical half life of 33 hours.