3D-nanostructured boron-doped diamond for microelectrode array neural interfacing

Abstract

The electrode material is a key element in the design of long-term neural implants and neuroprostheses. To date, the ideal electrode material offering high longevity, biocompatibility, low-noise recording and high stimulation capabilities remains to be found. We show that 3D-nanostructured boron doped diamond (BDD), an innovative material consisting in a chemically stable material with a high aspect ratio structure obtained by encapsulation of a carbon nanotube template within two BDD nanolayers, allows neural cell attachment, survival and neurite extension. Further, we developed arrays of 20-μm-diameter 3D-nanostructured BDD microelectrodes for neural interfacing. These microelectrodes exhibited low impedances and low intrinsic recording noise levels. In particular, they allowed the detection of low amplitude (10-20 μV) local-field potentials, single units and multiunit bursts neural activity in both acute whole embryonic hindbrain-spinal cord preparations and long-term hippocampal cell cultures. Also, cyclic voltammetry measurements showed a wide potential window of about 3 V and a charge storage capacity of 10 mC.cm(-2), showing high potentiality of this material for neural stimulation. These results demonstrate the attractiveness of 3D-nanostructured BDD as a novel material for neural interfacing, with potential applications for the design of biocompatible neural implants for the exploration and rehabilitation of the nervous system.

Carbon nanotube electrodes for retinal implants: A study of structural and functional integration over time

“…Examples of such coatings are IrO 2 and polyethylenedioxythiophene (PEDOT), with CSCs estimated at 28 mC/cm 2 and 75 mC/cm 2 , respectively [52]. Nanocrystaline diamonds have recently been considered for retinal stimulation showing promising biocompatibility [53] and a theoretical CSC of 10 mC/cm 2 when topographically enhanced with CNTs [54].…”

Flexible graphene transistors for recording cell action potentials

“…In recent years, an increasing effort is being dedicated to the development of a new generation of electronic devices that can further advance the interface to living cells and tissue. [1,2,3,4] Besides improving our understanding of the nervous system and the brain, [5] these devices can be applied in electrically-active prostheses to restore vision, [6] hearing, [7] or to find a solution to damaged motor or sensory functions. [8] While some of these applications exclusively rely on the electrical stimulation of cells or tissue, others also require the detection of the electrical activity of the nerve cells.…”

Monitoring the evolution of boron doped porous diamond electrode on flexible retinal implant by OCT and in vivo impedance spectroscopy

“…the bias window at which the current rises significantly, from -1.5V to +1.5V, thus assessing the 3V typical window of pure diamond materials, which confirms that such material was indeed successfully integrated in the flexible electrodes. The peak observed at 1.1V on the diamond electrode voltammograms is attributed to the Cl oxidation as reported by Piret et al [22]. The capacitive background…”

“…This result is consistent since the impedance increases when reducing the diameter of the electrode. nanotubes [22]. The electrochemical impedance modulus of the electrode in the observed spectral range (100 Hz-50 kHz) does not compete with the best materials reported in the literature such as carbon nanotubes (CNTs) [31], PEDOT [32] or porous platinum [33], but it is also interestingly significantly lower than the value reported in the literature for nanocrystalline diamond (NCD) electrode [34] and close to other porous diamond electrode.…”

“…One common comparison figure is to assess the capacitance value at a reference frequency of 1kHz, and recently, remarkable new generation of porous boron doped diamond materials have been reported with intrinsically high capacitance thus adding to their advantages for neural interfacing [21,22].…”