Nanoflex for neural nanoprobes

Scaling up the number of recording sites for neuronal interfaces while minimizing the impact on brain function presents several engineering challenges. Here we focus on miniaturizing the probe cable interconnects to minimize tethering forces at the probe-brain interface, allow multiple probes to be implanted in adjacent brain regions, and decrease damage associated with deep brain implants. We fabricated 32- and 64-channel Parylene C cables ranging in length from 7-65 mm for use with next-generation silicon probes (`nanoprobes´). To reduce cable width, 10 μm pitch leads were patterned on two layers sandwiched between three layers of parylene (overall thickness 15μm). The compliance of the cables was modeled using Timoshenko beam bending theory. Reliability was assessed using accelerated lifetime testing with electrochemical impedance monitoring. These `nanoflex´ cables are an order of magnitude smaller and two orders of magnitude more flexible than existing commercially available devices, a key technology for making viable long term, high-density neuronal recordings in both superficial and deep brain structures.