A new MEMS neural probe integrated with embedded microfluidic channel for drug delivery and electrode array for recording neural signal

We present a multi-functional silicon neural probe that consists of a microfluidic channel for selective delivery of a precise quantity of a chemical and multiple recording electrodes to simultaneously monitor the effects of drug delivery. A 30-μm wide, 10-μm high microfluidic channel is embedded in the probe substrate by anodic bonding, thermal reflowing and polishing a glass wafer to seal the channel. 10-μm-by-10-μm four multiple recording sites are located near the outlet port to record neural spike signals in response to the delivered drug. The fabricated 150-μm-thick probe exhibits a flow rate of 0.2 μl/min at the input air pressure of 200 kPa and an average impedance value of 3.0 MΩ at 1 kHz. In addition, the functionality of this probe is demonstrated through an in vivo experiment where neural spike signals at the hippocampus of an anesthetized mouse are successfully detected and recorded.