Vertically Aligned Carbon Nanofiber Arrays: An Advance toward Electrical–Neural Interfaces

High-density 3D pyramid-shaped microelectrode arrays for brain-machine interface applications

“…The impedance of CNT electrodes was significantly lower than Pt but still not as low as iridium oxide [5]. Iridium oxidecoated electrodes were not considered because of deterioration of long term stability if used beyond their charge injection limits [152].…”

“…In fact, instead of spaghetti-like structures usually obtained in CVD, plasma allows to grow well-aligned, individual and free-standing nanotubes with uniform diameters [151]. Such geometry increases the accessible surface area of CNTs leading to low impedance and it may also permit the direct excitation of a single neuron [152]. Furthermore, lower growth temperatures relative to CVD (<400°C) are possible since high-energy electrons present in the discharge plasma, supply the energy necessary for chemical reactions in the gas [153].…”

“…Iridium oxide-coated electrodes were not considered for charge delivery capacity (QCDC) and charge injection capacity (Qinj) because of harmful pH-value changes during electrical stimulation [152].…”

“…A uniform free standing of nanotubes are desired as an electrical-neural interface. This can be achieved by depositing a conformal layer of conductive polymers such as polypyrrole (Ppy) around the CNTs [152].…”

Polymeric Thin Film Technology for Neural Interfaces: Review and Perspectives

“…Recently, the use of carbon nanotubes (Tasis et al, 2006) attracted significant attention of several groups for the development of novel neuronal interfaces (Nguyen et al, 2007Nguyen et al, 2006, Gabay et al, 2007. Composite materials containing multi-walled CNTs have shown the ability to limit astrocyte production of glial scarring, while maintaining good neuronal connections (McKenzie et al, 2004).…”