Parylene neural probe with embedded CMOS multiplexing amplifier.

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Neural probes require reliable integration of microelectronic components for signal acquisition.
• Existing methods for chip-to-probe integration can be complex and may affect probe performance.
• Parylene-based neural probes offer biocompatibility and flexibility for neural interfacing.

Purpose of the Study:

• To present a novel method for embedding integrated circuit chips within parylene neural probes.
• To demonstrate the electrical and physical connection of chips to probes using Anisotropic Conductive Film (ACF).
• To evaluate the performance and insulation of the assembled neural probe system.

Main Methods:

• Fabrication of a custom 8-to-1 multiplexing amplifier using a 0.18 μm CMOS process.
• Integration of the CMOS chip onto a parylene neural probe using Anisotropic Conductive Film (ACF).
• In vitro insulation testing of the assembly up to 150 hours.
• Performance evaluation of the amplifier in air and phosphate-buffered saline (PBS).

Main Results:

• Successful electrical and physical connection of an 830 μm x 1030 μm die to a parylene probe.
• Adequate insulation of the assembly verified for 150 hours in vitro (testing ongoing).
• Preliminary amplifier tests showed comparable performance in air and PBS.
• Demonstrated signal amplification of approximately 200 V/V for neural signals in saline.

Conclusions:

• The presented ACF-based method provides a viable approach for embedding integrated circuit chips in parylene neural probes.
• The integrated system demonstrates robust electrical connectivity and adequate insulation for neural recording applications.
• The custom CMOS amplifier shows promising performance in saline, indicating potential for in vivo neural signal processing.