The use of a novel carbon nanotube coated microelectrode array for chronic intracortical recording and microstimulation

Micro-electrode arrays (MEAs) have been used in a variety of intracortical neural prostheses. While intracortical MEAs have demonstrated their utility in neural prostheses, in many cases MEA performance declines after several months to years of in vivo implantation. The application of carbon nanotubes (CNTs) may increase the functional longevity of intracortical MEAs through enhanced biocompatibility and charge injection properties. An MEA metalized with platinum (Pt) on all electrodes had a CNT coating applied to the electrodes on half of the array. This Pt/Pt-CNT MEA was implanted into feline motor cortex for >1 year. Recordings of action potentials and 1 kHz impedance measurements were made on all electrodes to evaluate device functionality. Additionally, electromyogram (EMG) responses were evoked using micro-stimulation via the MEA to measure device performance. These metrics were compared between Pt and Pt-CNT electrodes. There was no significant difference in the data acquisition or micro-stimulation performance of Pt and the Pt-CNT electrodes. However, impedances were lower on the Pt-CNT electrodes. These results demonstrate the functionality of CNT coatings during chronic in vivo implantation. The lower impedances suggest that for microstimulation applications CNT coatings may impart enhanced interface properties.