Design of a CMOS-based Multichannel Integrated Biosensor Chip for Bioelectronic Interface with Neurons

In this paper we present the design and prototyping of a 24-channel mixed signal full-customized CMOS integrated biosensor chip for in vitro extracellular recording of neural signals. Design and implementation of hierarchical modules including microelectrode electrophysiological sensors, analog signal buffers, high gain amplifier and control/interface units are presented in detail. The prototype chip was fabricated by MOSIS with AMI C5 0.5 mum, double poly, triple metal layer CMOS technology. The electroless gold plating process is used to replace the aluminum material obtained from the standard CMOS process with biocompatible metal gold in the planner microelectrode array sensors to prevent cell poisoning and undesirable electrochemical corrosion. The biosensor chip provides a satisfactory signal-to-noise ratio for neural signals with amplitudes and frequencies within the range of 600 muV - 2 mV and 100 Hz to 10 KHz, respectively.