INTEGRATED ENZYME THIN FILM METAL ECTRODES

Abstract

Miniaturized electrodes have been constructed as transducers of biosensors. Onto oxidized silicon wafers Ti as adhesion and Au as conductivity layers have been deposited. A 120nm Pt layer forms the upper layer for amperometric and impedimetric electrodes, whereas Sb/SbO or Ag/AgCl composite layers are the electro-chemically active layers of the potentiometric and the reference electrodes, respectively. They can be combined in different shapes and sizes at the chips and applied in test strips or flow through devices. The amperometric electrodes with a upper Pt layer are stable at potentials of water electrolysis. The reference Ag/AgCl composite electrode is more resistent against light and dissolution than the common surface bound AgCl layers at silver.The pH dependency of the Sb/SbOelectrode is 56 + 0.1 mV/pH and was observed to be stable over a period of about 30 days, which should be useful for the normal working time of biosensors.