Flexible silicon-polymer neural probe rigidified by dissolvable insertion vehicle for high-resolution neural recording with improved duration

This study reports on a novel concept for silicon (Si)-based intracortical neural probes with improved mechanical flexibility and reduced dimensions. Microelectrode arrays with cross-sections as small as 50 × 120 μm2 and polyimide ribbon cables of similar width but a thickness of only 11 μm are assembled into slender, flexible recording systems. As their interfacing section is reduced to the width of the probe shank, the Si-based electrode array can be completely implanted into brain tissue while the cable creates the interface to the external instrumentation. This hybrid probe concept allows the reduction of the implanted volume and probe stiffness by factors of ca. 5 and 1400, respectively, compared to conventional Si probes. As a consequence, the stability of neural recording is expected to be increased. For probe implantation, the probe is stiffened by a bio-dissolvable polymer mold around the probe using the centrifuge-based molding of polyethylene glycol.