Journal of the Electrochemical Society, Vol.146, No.8, 2965-2967, 1999
Stabilization of wired glucose oxidase anodes rotating at 1000 rpm at 37 degrees C
The stability of glucose electro-oxidizing anodes rotating at 1000 rpm at 37 degrees C was investigated. The anodes were made by coating 3 mm diam vitreous carbon disks with a cross-linked, electron conducting redox hydrogel, which electrically connected reaction centers of glucose oxidase to the electrode. The endurance of the hydrogel films under the shear stress resulting from the rotation depended on their cross-linking. Periodate oxidation of enzyme oligosaccharides, thereby forming multiple Schiff bases which cross-linked the enzyme and the redox polymer, combined with additional cross-linking by a diepoxide, resulted in toughened electrocatalytic films that survived the shearing caused by the rotation. The main residual cause of damage to the toughened films was chemical attack by H2O2, an undesired by-product. Overcoating the "wired" enzyme film with a layer of immobilized catalase reduced such damage. The current density of glucose electro-oxidation of the stabilized rotating electrodes was at 50 mM concentration, 420 mu A cm(-2), decaying in the 11 h test period by 28 mu A/cm(2).