Development of silicon electrode neural probe and acute study on implantation mechanics

Abstract

The silicon probe with highly P-doped Si electrodes was realized on 8 inch SOI wafer through standard CMOS process. After additional coatings of nano-composite (CNTs + Au nanoparticles) on silicon electrodes, the functionality of neural recording was verified with a low noise level (< 20 μV) during in vivo recording on rat brain. With built-in silicon nanowires (SiNWs) based piezoresistiors connected in full bridge structure, the capability of monitoring probe mechanical behavior was firstly examined with the probe buckling experiments and further proven through in vivo implantations on rat brain. Besides the large buckling mechanics (during probe insertion), the physiological brain micro-motion (e.g. caused by respiration) was successfully picked up by integrated SiNWs strain sensors. The integrated neural device (including both neural electrode and localized strain sensor) provides the possible research platform to practically understand the correlation between the recorded electrical neural signal and the brain micro-motion.

Liquid Metal-Based Electrode Array for Neural Signal Recording

“…One common strategy is to print or spray the conductive materials on a soft substrate such as polydimethylsiloxane (PDMS) [15], polyimide (PI) [16], or polyamide (PA) [17]. Silicon nanowires [18], carbon nanotubes [19], graphene [17,20], and Poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) [21] have been used for the fabrication of brain electrodes recently. However, the electronic conductivity of these materials (for example, graphene is ~5.2 × 10 3 S/m, and PEDOT:PSS is ~2.8 × 10 3 S/m) is much lower than that of the metal materials (such as Pt ~9.4 × 10 6 S/m, Ag ~6.8 × 10 7 S/m, and Au ~4.3 × 10 7 S/m).…”