Long Porous Silicon Probe Array for Neural Recordings

Neural probes are the main component of a Brain-Computer Interface (BCI) that enables a communication pathway between the brain and an external device. Neural probes have a wide design space in terms of size, shape, and function. Here, we present novel elongated neural probe with multiple recording sites that can reach than 10mm deep regions in the brain. Reaching such depth offer the possibility of recording of cognitive signals required to operate cognitive prosthetics. The impedance of the recording sites on the probes is on the order of 500 kΩ at 1 kHz, which is suitable for neurophysiological recordings. The probes were made porous using Xenon Difluoride (XeF2) dry etching to improve the biocompatibility and their adherence to the surrounding neural tissue. Numerical studies were performed to determine the reliability of the porous probes. We implanted the elongated probe in rats and show that the elongated probes are capable of simultaneously recording both spikes and local field potentials (LFPs) from various recording sites.

Keywords: Cognitive neural prosthetics; Brain computer interfaces; Porous silicon; Microprobes