(Invited) Electrochemical Biosensors Based on CMOS LSI Chips

Abstract

We have been working on electrochemical biosensing using CMOS chip as a platform. Three major electrochemical methods, amperometric (voltammetric), potentiometric, and impedance methods, are aimed to be done by electrodes on a CMOS chip. In amperometric measurement, carbon-ink is used to form electrochemically-stable electrodes instead of expensive gold electrode formation by photolithography. Enzymes and mediator (redox) molecules are immobilized in pieces of chromatography paper, and layers of such paper are placed directly on CMOS chip. Both amperometric and potentiometric detection of glucose concentration have been demonstrated. We have also been working on computer simulation and modeling of the three electrochemical measurements done by microscale electrodes on CMOS chip. Examples include 3D amperometric current simulation of 2D microelectrode array on a CMOS chip, potentiometric measurement of pH and DNA on an ion-sensitive field-effect transistor, as well as living cell monitoring based on impedance method. We also design CMOS integrated circuits for on-chip biosensing based on the electrochemical methods.