ENZYME MICROELECTRODE ARRAY STRIPS FOR GLUCOSE AND LACTATE

Microdisk arrays, prepared by combination of thick-film technology and laser micromachining procedures, serve as hosts for glucose oxidase and lactate oxidase, to yield effective amperometric test strips for glucose and lactate. The enzymes are localized electrochemically within the pores of the 15-mum disks via codeposition with rhodium or platinum. Scanning electron microscopy elucidates the unique growth patterns of the metalized enzyme layer within the individual laser-drilled holes. The strong and preferential catalytic action of the rhodium particles toward the oxidation of the enzymatically liberated hydrogen peroxide offers highly selective monitoring of the corresponding substrate and eliminates the need for membrane barriers. The high selectivity is coupled to high sensitivity accrued from the array character and large microscopic area of the individual disks. Such a simple one-step electrochemical immobilization onto microelectrode arrays offers fast and sensitive measurements from small sample volumes and can be used to mass produce reliable enzyme-based diagnostic strips.