Accordingly, special efforts were put to
immobilize the mediators. Reagentless second generation
biosensors were made by immobilization of glucose oxidase
in ferrocene-modified polypyrrole9 as well as other polymers.
10,11 Covalent linking of the ferrocene derivative to the
enzyme molecule12,13 seems to be even more complicated and
less successful. Phenothiazine linking to glucose oxidase is also
reported displaying catalytic cyclic voltammograms of the
enzyme electrode.