Molecular recognition with enzymes and with enzyme-labelled immuno and genomic electrodes based, respectively, on the antigen-antibody interaction and single-strand DNA hybridization with self-immobilized redox relays to generate an electrical signal can be integrated into circuits. These systems can be integrated in future generation of bichips. In our laboratory layer-by-layer supramolecular structures composed of alternate layers of negatively charged enzymes and cationic redox polyelectrolytes have been assembled. Different enzymes such as glucose oxidase, lactate oxidase, soybean peroxidase and proteins such as immunoglobulins (IgG) have ben studied in these multilayers. In these modified electrodes, with highly spatially organized structures, we are interested in the electrical communication of the biomolecules with the underlying electrodes.

Chemically modified high molecular weight poly(allylamine) with [Os(bpy)2ClPyCHO]+ redox centers was used as redox polymer mediator to wire the enzymes to the electrodes.

In this presentation we report on experimental studies of these systems in order to understand and therefore to improve the molecular recognition, redox mediation and electrical signal generation in amperometric devices and molecular transistors responsive to the biochemical environment.

Information on the amount of biomolecules deposited, number of redox centers, electrical communication and catalysis can be gained with a combination of different experimental techniques.Evidence from different techniques such as quartz crystal microbalance (qcm) with electroacoustic impedance, ellipsometry, atomic force microscopy (AFM), cyclic voltammetry and enzyme electrocatalytic studies will be presented.

The surface concentration of electrically wired enzyme molecules present in the multilayers and the rate of enzyme reoxidation or reduction by the redox mediator has been assessed for the different structures and correlated with the structure of these multilayers from ellipsometry and AFM.