Abstract

This paper presents an integrated, protein-based, biosensor that can be scaled to form high-density, multi-analyte sen-sor arrays physically integrated on a signal conditioning circuit die. A fully scalable, post-CMOS-compatible, three-electrode interface to biochemical sensors has been devel-oped. A silicon substrate electrode system, consisting of Ti/Au working and auxiliary electrodes and a Ti/Au/Ag/AgCl reference electrode has been adapted to biomimetic sensors. The functional Ag/AgCl reference electrode is isolated from the environment using a Nafion cation-exchange membrane to extend operation lifetime. To complete the sensor structure, lipid bilayers have been deposited in passivation layer openings formed over indi-vidual working electrodes using a special tethering mole-cule. Total internal reflection microscopy (TIRFM) studies were done to confirm that a wide range of proteins, such as dehydrogenase enzymes and ion channels, can then be em-bedded into the lipid bilayers. These results verify the po-tential to form highly selective recognition elements with direct physical connection to readout electronics on the supporting silicon substrate.