Prussian Blue-Based First-Generation Biosensor. A Sensitive Amperometric Electrode for Glucose

Abstract

A first-generation amperometric glucose biosensor based on a Prussian Blue-modified electrode was developed. Prussian Blue was found to be a better electrocatalyst for hydrogen peroxide reduction than platinum. H 2 O 2 was detected at the Prussian Blue-modified electrode in the presence of oxygen by both electrooxidation and electroreduction. The glucose amperometric biosensor was made by glucose oxidase immobilization onto a Prussian Blue-modified electrode with a Nafion layer. The biosensor response exhibited a linear dependence on analyte concentration in the range 1 x 10 -6 -5 x 10 -3 M. The cathodic current density after addition of 10 -6 M glucose was 0.18 μA/ cm 2 . When hydrogen peroxide produced via the enzyme reaction was detected by electroreduction, the biosensor response was independent of reductants. This amperometric biosensor is expected to obey the requirements for noninvasive diagnostics.