Fabrication and characterization of implantable silicon neural probe with microfluidic channels

In this paper, a silicon-based neural probe with microfluidic channels was developed and evaluated. The probe can deliver chemicals or drugs to the target neurons while simultaneously recording the electrical action of these neurons extracellularly. The probe was fabricated by double-sided deep reactive ion etching (DRIE) from a silicon-on-insulator (SOI) wafer. The fluidic channels were formed with V-shape groove etching on the silicon probe and sealed with silicon nitride and parylene-C. The shank of the probe is 4 mm long and 120 mu m wide. The thickness of the probe is 100 mu m. The probe has two fluidic channels and two recording sites. The microfluidic channels can withstand a pressure drop as much as 30 kPa and the flow resistivity of the microfluidic channel is 0.13 mu L min-1 kPa-1. The typical impedance of the neural electrode is 32.3 k Omega at 1 kHz at room temperature.