Large‐Scale and High‐Density Microelectrode Array on a Complementary Metal Oxide Semiconductor Chip for Biochemical Applications

Multichannel electrochemical sensing technology has been widely applied in the fields of chemical and biological applications. By combining complementary metal oxide semiconductor (CMOS) technology to construct microelectrode array (MEA) chips, the throughput and spatiotemporal resolution could be vastly boosted by the tens of thousands of electrodes on the chip. This article describes a large‐scale and high‐density electrochemical sensing and reactions‐driven CMOS MEA chip demonstrated with various chemical and biological applications. The chip integrates 24 576 gold microelectrodes with a 18 µm pitch, achieving a per‐electrode sampling rate of 140 kS/s and a full‐array frame rate of 5 Hz. It also incorporates an associated switch matrix, 24 integrated potentiostats and digital control circuits. We studied and suppressed the cross talk among multiple electrodes working in the solution with finite element analysis and experiments. The large‐scale and high‐spatiotemporal resolution electrochemical sensing capability of this chip was proven by 3D voltammetry. For driving electrochemical reactions, bubble generation for primary neuron detachment at selected electrodes, electrode electroplating, and DNA synthesis were demonstrated.