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 3 7 degrees C was investigated. The anodes were made by coating 3 mm diam vit reous carbon disks with a cross-linked, electron conducting redox hydrogel, which electrically connected reaction centers of glucose oxidase to the el ectrode. The endurance of the hydrogel films under the shear stress resulti ng from the rotation depended on their cross-linking. Periodate oxidation o f enzyme oligosaccharides, thereby forming multiple Schiff bases which cros s-linked the enzyme and the redox polymer, combined with additional cross-l inking by a diepoxide, resulted in toughened electrocatalytic films that su rvived the shearing caused by the rotation. The main residual cause of dama ge to the toughened films was chemical attack by H2O2, an undesired by-prod uct. Overcoating the "wired" enzyme film with a layer of immobilized catala se 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). (C) 1999 The Elect rochemical Society. S0013-4651(98)12-041-4. All rights reserved.