A Reconfigurable CMOS Microelectrode Array Featuring 24,576 Electrodes for Chemical and Electrical Neural Recording.

OBJECTIVE: This study aims to develop a high throughput, high-density, and reconfigurable CMOS microelectrode array (MEA) chip for chemical and electrical recording of biological neural networks. METHODS: The continuous time/discrete-time current sensing architecture is integrated on a single chip to support electrochemical and electrophysiological measurements within the same system. The readout achieves 24,576 electrodes, an input-referred noise density of 2 fA/√Hz, a bandwidth of 5 kHz/70 kHz, and 24/384 simultaneous output channels for chemical/electrical recording, respectively. For electrochemical measurements, inter-electrode chemical crosstalk is suppressed to improve the spatial resolution of array-based electrochemical measurements. RESULTS: The proposed chip demonstrates electrochemical sensing at individual electrodes, quantitative detection of dopamine in prepared solution, and dynamic electrochemical imaging with high spatial and temporal resolution. For electrophysiological measurements, spontaneous extracellular biocurrent is successfully recorded from primary neurons confirming the capability of the system for cell-level electrophysiological current sensing. CONCLUSION: Experimental results verify the applicability of the proposed MEA in recording electrochemical and electrophysiological signals from various biological samples, highlighting its potential as a versatile bioelectronic platform for multimodal neural interface applications. SIGNIFICANCE: Compared with other MEAs, the proposed chip supports both neurotransmitter-related chemical sensing and neural current recording on the same hardware platform. Therefore, it provides a promising tool for studying the interaction between chemical and electrical signaling in biological neural networks.