Fabrication of High-Density Multimodal Neural Probes Based on Heterogeneously Integrated CMOS.

Area of Science:

• Neuroscience and Bioengineering
• Advanced Neural Interface Technology

Background:

• Understanding brain function requires simultaneous recording of electrical activity and cell-type-specific dynamics.
• Existing neural probes, such as MEMS and CMOS, face limitations in channel density or high costs, hindering broader adoption.
• High-density neural recording is crucial for deciphering complex brain mechanisms and neurological disorders.

Purpose of the Study:

• To develop a novel, cost-effective neural probe architecture for high-density simultaneous electrical and optical recording.
• To overcome the limitations of current neural interface technologies regarding cost and channel density.
• To enable advanced brain research through integrated multimodal neural sensing.

Main Methods:

• Applied simplified post-Complementary Metal-Oxide-Semiconductor (CMOS) processing on a multi-project wafer (MPW) to reduce per-wafer cost by nearly two orders of magnitude.
• Utilized decoupled sensor customization, defining CMOS front-end circuits and post-processing multimodal sensors (electrodes and photodiodes).
• Engineered a 13-shank probe integrating 416 electrodes and 832 photodiodes with complete on-chip signal processing.

Main Results:

• Achieved a significant reduction in fabrication cost through simplified post-CMOS processing.
• Successfully integrated a high density of electrodes (416) and photodiodes (832) on a single probe.
• Demonstrated simultaneous high-density electrical and optical recording capabilities, validated in vitro and in vivo.

Conclusions:

• The proposed approach enables a cost-effective method for producing advanced neural probes.
• The developed probe architecture facilitates simultaneous high-density electrical and optical neural interfacing.
• This innovation represents the first fully integrated active multimodal neural probe for comprehensive brain activity monitoring.