Self-supporting carbon nanotube films as flexible neural interfaces

Abstract

Advances in neural interface technologies have sought to identify electroactive materials that are able to translate neural depolarisation events into digital signals or modulate neural firing through ionic or electrical stimulation with greater efficiency. An ideal material for neural recording and/or stimulation should possess low electrical impedance coupled with a high cathodic charge storage capacity (CSCC), charge injection capacity (CIC) and electroactive surface area (ESA), as well as optimal mechanical biomimicry. In this study, we present the robustness of self-supporting CNT films as neural interfaces, combining advantageous electrical and mechanical properties with high cytocompatibility. Films were observed to possess a high CSCC (29.95 ± 0.91 mC cm−2), CIC (352 ± 5 μC V−1 cm−2) and ESA (0.908 ± 0.053 cm2), low impedance (110 Ω at 1 kHz), low resistance (75 ± 13 Ω) and high capacitance (378 ± 9 μF cm−2), and outperformed Pt control electrodes. Self-supporting CNT films were also found to facilitate neuron growth and decrease the presence of reactive astrocytes in a mixed neural cell population. Self-standing CNT films were shown to be promising materials for the design of flexible and cytocompatible neural interfaces.