Parylene neural probe with embedded CMOS multiplexing amplifier.

We present a method for embedding integrated circuit chips in parylene neural probes where Anisotropic Conductive Film (ACF) electrically and physically connects the chip to the probe. Adequate insulation of the assembly is verified up to 150 h in vitro (testing ongoing). A custom-designed 8-to-1 multiplexing amplifier for neural application was fabricated in a 0.18 μm CMOS process. As a feasibility demonstration, the $830 \mu \mathrm {m}\times 1030 \mu \mathrm {m}$ die was connected to a parylene probe on a glass substrate. Preliminary results of the amplifier tests indicate similar performance in air and in phosphate buffered saline (PBS), and demonstrate around 200 V/V amplification of signals in saline.