Carbon-Nanotube-Coated Surface Electrodes for Cortical Recordings In Vivo

Abstract

Current developments of electrodes for neural recordings address the need of biomedical research and applications for high spatial acuity in electrophysiological recordings. One approach is the usage of novel materials to overcome electrochemical constraints of state-of-the-art metal contacts. Promising materials are carbon nanotubes (CNTs), as they are well suited for neural interfacing. The CNTs increase the effective contact surface area to decrease high impedances while keeping minimal contact diameters. However, to prevent toxic dissolving of CNTs, an appropriate surface coating is required. In this study, we tested flexible surface electrocorticographic (ECoG) electrodes, coated with a CNT-silicone rubber composite. First, we describe the outcome of surface etching, which exposes the contact nanostructure while anchoring the CNTs. Subsequently, the ECoG electrodes were used for acute in vivo recordings of auditory evoked potentials from the guinea pig auditory cortex. Both the impedances and the signal-to-noise ratios of coated contacts were similar to uncoated gold contacts. This novel approach for a safe application of CNTs, embedded in a surface etched silicone rubber, showed promising results but did not lead to improvements during acute recordings.

Implantable neural electrodes: from preparation optimization to application

“…79 CNTs can be used as a coating material for neural electrodes. 80 Additionally, the one-dimensional material CNT yarn derived from CNTs is an ideal choice for the long-term recording of specific nerve signals because its size and flexibility are similar to those of the actual nerve, so they can be inserted into specific nerves and remain for several months. McCallum et al prepared a soft axonal-sized CNT yarn electrode.…”

Cell adhesion molecule immobilized gold surfaces for enhanced neuron‐electrode interfaces

“…Invasive or penetrating neuroprosthetic devices are powerful tools toward the diagnosis or treatment of neurological disorders (e.g., epilepsy, Parkinson's disease, dementia), deficiencies (e.g., cognitive or hearing), and studying neurobiological processes 1–5 . Most of these devices, including micromachined microelectrodes, wire‐based arrays, and polymer microelectrodes, work on the principle of delivering electrical signals to neurons or recording neuronal activity through local field potentials or action potentials 6–8 …”

Biocompatibility Testing of Liquid Metal as an Interconnection Material for Flexible Implant Technology

“…Flexible surface electro-cortical grid arrays (ECoG) are a valuable alternative to penetrating multi-electrode arrays (MEA). Their usability in both acute and chronic recordings is under investigation for numerous material combinations [1][2][3][4] and their potency for good recordings has been shown as well [2,3]. Yet they are limited in their flexibility by the rigid materials used for their conductive pathways.…”