Polypyrrole/copper hexacyanoferrate hybrid as redox mediator for glucose biosensors

A copper containing Prussian Blue analogue was incorporated into a conducting polypyrrole film. The modified electrode was synthesized through an electrochemical two-step methodology leading to very stable and homogeneous hybrid films. These electrodes were proved to show excellent catalytic properties towards H₂O₂ detection, with a performance higher than those observed for Prussian Blue and other analogues. Electrochemical impedance spectroscopy experiments demonstrated that the excellent performance of these hybrid films is strongly related to the electronic conductivity of the polymeric matrix that is wiring the copper hexacyanoferrate sites. A glucose biosensor was built-up by the immobilization of glucose oxidase; the sensitivity obtained being higher than other biosensors reported in the literature even in Na⁺ containing electrolytes.