IMAGING OF MICROSTRUCTURED BIOCHEMICALLY ACTIVE SURFACES BY MEANS OF SCANNING ELECTROCHEMICAL MICROSCOPY

Scanning electrochemical microscopy (SECM) has been used to create and to image thin film structures of functionalized polypyrrole, to which glucose oxidase has been covalently immobilized. In addition, the SEC M was applied to optimize the quality of all steps of this microfabric ation process. For this purpose, imaging of the obtained structures wa s performed in the conventional feedback mode of the SECM with ferroce ne derivatives or [Os (bpy)(2) fpy] (bpy = 2,2'-bipyridine, fpy = 4-fo rmylpyridine). The same working mode is also used for the enzyme-modif ied microstructures exploiting the ability of glucose oxidase to accep t the oxidized forms of these inorganic transition metal complexes as artificial cofactors. Successive images in the absence and presence of the enzymes's substrate glucose added to the mediator solution allowe d us to distinguish between the mediator regeneration caused by a hete rogeneous electron-transfer reaction at the underlying gold support an d the enzyme-mediated feedback. Prospects for the development of minia turized biosensors are discussed. (C) 1997 Published by Elsevier Scien ce Ltd.