A flexible and implantable microelectrode arrays using high-temperature grown vertical carbon nanotubes and a biocompatible polymer substrate

Abstract

This paper presents a novel microelectrode arrays using high-temperature grown vertically aligned carbon nanotubes (CNTs) integrated on a flexible and biocompatible parylene substrate. A simple microfabrication process is proposed to unite the high quality vertical CNTs grown at high temperature with the heat sensitive parylene substrate in a highly controllable manner. Briefly, the CNTs electrode is encapsulated by two layers of parylene and the device is released using xenon difluoride (XeF2). The process is compatible with wafer-scale post complementary metal oxide semiconductor integration. Lower impedance and larger interfacial capacitance have been demonstrated using CNTs compared to a Pt electrode. The flexible CNT electrodes have been utilized for extracellular neuronal recording and stimulation in rats. The signal-to-noise ratio of the device is about 12.5. The threshold voltage for initiating action potential is about 0.5 V.

Carbon multi‐electrode arrays as peripheral nerve interface for neural recording and nerve stimulation

“…The quality of the EMG recordings was evaluated in terms of the SNR which is the ratio of the EMG amplitude to the background noise amplitude as described in our previous study (Yi et al, ). The SNR of the EMG recorded by the 3D‐printed carbon electrodes (41.22 ± 5.14) was significantly higher than that of the Pt electrodes (16.62 ± 4.80) (paired t test, p < 0.001), while the sciatic nerve was stimulated by Pt electrodes.…”

“…The quality of the EMG recordings was evaluated in terms of the SNR which is the ratio of the EMG amplitude to the background noise amplitude as described in our previous study (Yi et al, 2015).…”

“…Although those materials can be used for nerve signal recording and stimulating, performance in long‐term applications has been unsatisfactory due to shortcoming in mechanical modulus, electronic transfer efficiency, signal sensitivity, chemical stability and biocompatibility. Other materials selected for electrode fabrications have included tungsten (Lai, Albaugh, Kao, Younce, & Shih, ), silicon (Campbell, Jones, & Normann, ), ceramics (Moxon, Leiser, Gerhardt, Barbee, & Chapin, ), flexible substrates (Cheung, Renaud, Tanila, & Djupsund, ), and carbon nanotube (An, Kim, Hahn, & Lim, ; Yi et al, ). Successful recordings and stimulating of a nerve interface depend on many factors, including the impedance and size of the electrode.…”

Interfacing Neurons with Nanostructured Electrodes Modulates Synaptic Circuit Features

“…[5] In this line, a series of flexible electrodes have been proposed, [18][19][20] but only a few combine flexibility with nanostructure. [21,22,23] For instance, Rogers and colleagues described a bio-interfaced system based on ultrathin electronics supported by bioresorbable substrates of silk fibroin, [18] which assures minimal stresses on the tissue and highly conformal coverage. Authors proved the utility of these interfaces to record neural activity in the feline visual cortex.…”

Versatile Flexible Graphene Multielectrode Arrays

“…The combination of MEAs and flexible substrates has gained much attention recently, specifically when combined with carbon-based materials like carbon nanotubes (CNTs), which exhibit great performance and flexibility [13,14]. There are several ways to build devices with carbon materials.…”