NEW ELECTROCATALYTIC BIOMOLECULAR INTERFACE FOR FABRICATING A FRUCTOSE DEHYDROGENASE-BASED SENSING SYSTEM

An enzyme electrode was fabricated by coupling a pyrroloquinoline quinone (PQQ)-containing oxidoreductase with a novel electrode material, TTF-TCNQ conducting salt in a polypyrrole matrix. The enzyme electrode was characterized by direct electron transfer between the reduced prosthetic moiety (PQQH2) and the transducing material at a less extreme potential due to the electrocatalytic function of the organic conducting salt. The oxidation of the reduced enzyme occured at 0.2 V vs. Ag/AgCl. The combination of the organic conducting salt and the conductive polymer exhibited an effective molecular interface where direct electron transfer between the PQQ enzyme and the transducing electrode proceeded at a less extreme potential. Here the conductive polymer matrix played important roles, i.e., facilitation of smooth electronic communication and matrix of enzyme immobilization. On the other hand, TTF-TCNQ played another role, i.e., electrocatalysis in the regeneration of fructose dehydrogenase. The resulting amperometric fructose sensor is Promising, as it was operated at a less extreme potential.