Design of a CMOS-based multichannel integrated biosensor chip for bioelectronic interface with neurons

Area of Science:

• Biomedical Engineering
• Neuroscience
• Electrical Engineering
• Materials Science

Background:

• Accurate in vitro extracellular recording of neural signals is crucial for understanding brain function and disease.
• Existing biosensor technologies face challenges with biocompatibility, signal-to-noise ratio, and integration.

Purpose of the Study:

• To design and prototype a novel 24-channel mixed-signal, full-customized CMOS integrated biosensor chip.
• To enable high-fidelity in vitro extracellular recording of neural signals for research applications.

Main Methods:

• Development of hierarchical modules including microelectrode sensors, analog signal buffers, high-gain amplifiers, and control/interface units.
• Fabrication using AMI C5 0.5 microm CMOS technology with double poly and triple metal layers.
• Application of electroless gold plating to replace aluminum with biocompatible gold on microelectrode array sensors.

Main Results:

• Successful design and prototyping of a 24-channel mixed-signal CMOS biosensor chip.
• The gold-plated microelectrodes demonstrated enhanced biocompatibility, preventing cell poisoning and corrosion.
• The biosensor chip achieved a satisfactory signal-to-noise ratio for neural signals (600 microV - 2mV, 100 Hz - 10 KHz).

Conclusions:

• The developed CMOS biosensor chip is a promising platform for advanced in vitro neural signal recording.
• The integration of biocompatible gold electrodes enhances device longevity and data integrity.
• This technology supports future research in neurobiology and the development of neural interfaces.