Conventional neural interfaces consist of microelectrode arrays (MEAs) that are in close contact with neurons to record extracellular potential or stimulate electrical activity. However, due to the relative large microelectrode size, these MEAs are not capable of extracting intracellular signals, which is of particular interest in restoring functional loss of limb control of individuals with spinal cord injury or stroke. MEAs electrophysiological recordings still faces two major challenges, the inherent noisy data and the limited spatial resolution. These problems especially limit the accuracy and reliability of the movement parameter due to the unreliable spike recording for long durations. The objective of this research is the fabrication and characterization of independently addressable nanoelectrode arrays (NEAs) and nanoelectrode probe arrays (NEPAs) for high-throughput recording of extracellular and intracellular electrophysiological measurements of neural activity. Objective: This objective will be achieved through the following specific aims: a) To develop gold nanoelectrode array platforms for simultaneous characterization of neural activity in multiple neurons, b) to develop direct methods for growing carbon nanotubes (CNTs) on the 256-gold nanotips using metal-catalyzed chemical vapor deposition, and c) to validate high throughput detection of neural activities. Intellectual Merit: The proposed research is innovative and transformative because for the first time, simultaneous extracellular and intracellular characterization using fine pitch NEA and NEPA technology will be developed to probe large numbers of neurons, while maintaining high spatial resolution, high signal-to-noise ratio, and excellent selectivity of neural interfaces. Because of the very large number of neurons that can be potentially interfaced, the resulting NEA and NEPA system will provide ground-breaking capabilities for parallel extracellular and intracellular characterization of neurons. Broader Impacts: The proposed NEA and NEPA system represents the frontier challenge for electrophysiological recording technology. This high throughput approach will advance electrophysiological characterization by enabling multiple neurons to be studied simultaneously while controlling other stimulation conditions to enable the reestablishment of the intricate connections between neurons after spinal injury or stroke. Results of the proposed research will be integrated into educational outreach activities by developing summer research experiences for K-12 and incoming university transfer students and by developing research experience for undergraduates.
