title: Evaluation of an amperometric glucose biosensor based on a ruthenium complex mediator of low redox potential.
abstract: An amperometric glucose ring-disk biosensor based on a ruthenium complex mediator of low redox potential was fabricated and evaluated. This thin-layer radial flow microsensor (10mul) with ring-disk working electrode displayed remarkable amperometric sensitivity. For Ru(3)(mu(3)-O)(AcO)(6)(Py)(3)(ClO(4)) (Ru-Py), a trinuclear oxo-acetate bridged cluster, a reversible redox curve of low redox potential and narrow potential window (redox potentials were -0.190 and -0.106V versus Ag/AgCl wire, respectively) was observed, which is comparable to many reported mediators such as ferrocene derivatives and other ruthenium complexes. The glucose and hydrogen peroxide assays were carried out with this complex-modified electrode Ru-Py-HRP-GOx/Nafion. The sensitivity was obtained 24nA (15.4mAM(-1)cm(-2)) for 10muM glucose and 126 nA (160mAM(-1)cm(-2)) for 5muM H(2)O(2), respectively with a working potential at 0V versus Ag/AgCl. Ascorbic acid was studied as interference to the glucose assay. The application of 0V potential versus Ag/AgCl did not avoid the occurrence of the oxidation of ascorbic acid, however, the pre-coating of ascorbate oxidase on the disk part of the ring-disk working electrode efficiently pre-oxidized the ascorbic acid and hence eliminated its interference on the glucose response. The practical reliability was also evaluated by assaying the dialysate from the prefrontal cortex of Wistar rats.
authors.affiliation: Department of Research and Development, Bioelectro Analytical Science Ltd., 1-36-6, Oshiage, Sumida-ku, Tokyo 131-0045, Japan.
authors.forename: Katsunobu
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Haisheng
authors.initials: H
authors.lastname: Zeng
authors.forename: Yi
authors.initials: Y
authors.lastname: Shen
authors.forename: Md Mahiuddin
authors.initials: MM
authors.lastname: Ahmed
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kato