Development of Silicon Probe With Acute Study on In Vivo Neural Recording and Implantation Behavior Monitored by Integrated Si-Nanowire Strain Sensors

The silicon probe with highly P-doped Si electrodes was realized on 8-in Silicon on insulator wafer through standard Complementary metal-oxide semiconductor process. By leveraging the same thin Si device layer (~100 nm), the built-in piezoresistive Si-nanowires (SiNWs) configured in full-bridge structure were also equipped along the probe shank for strain sensing. After additional coatings of nanocomposite (Carbon nanotubes + Au nanoparticles) on silicon electrodes, the functionality of neural recording was validated with a low noise level (<;20 μV) during in vivo neural recording on rat brain (CA1 region). The additional capability of monitoring probe mechanical behavior was first verified through the probe buckling experiments and further examined with implantations on rat brain (S1 region). Besides the large buckling mechanics, the physiological brain micromotion (e.g., caused by respiration) was successfully picked up by integrated SiNWs strain sensors, which would provide the research platform to practically understand the correlation between the electrical neural signal and the brain micromotion.