Electrodeposition of Enzymes on Miniature Electrodes

Abstract

This chapter reviews the electrodeposition of enzymes on miniature electrodes. One of the most important problems in the construction of miniature enzyme electrodes is the deposition of the enzymes in a spatially controlled way. This problem becomes particularly acute when multianalyte sensors are considered. An interesting solution is the direct deposition of proteins on an oppositely charged electrode, without using an electropolymerized matrix. The deposition is performed in two steps, electrochemical deposition from a concentrated protein solution, followed by crosslinking with glutaraldehyde. The enzyme electrodes based on glucose oxidase, urease, and catalase produced with this method is reported. It is found that by combining the two steps, though using more dilute protein solutions containing glutaraldehyde, one have produced a one-step deposition which allows deposits to be made from protein solutions as dilute as 0.01%. This technique allows electrodes with widths as low as 25 μm to be modified and gives stable deposits and large responses.