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Substrate arrays of iridium oxide microelectrodes for in vitro neuronal interfacing

Substrate arrays of iridium oxide microelectrodes for in vitro neuronal interfacing
Substrate arrays of iridium oxide microelectrodes for in vitro neuronal interfacing
The design of novel bidirectional interfaces for in vivo and in vitro nervous systems is an important step towards future functional neuroprosthetics. Small electrodes, structures and devices are necessary to achieve high-resolution and target-selectivity during stimulation and recording of neuronal networks, while significant charge transfer and large signal-to-noise ratio are required for accurate time resolution. In addition, the physical properties of the interface should remain stable across time, especially when chronic in vivo applications or in vitro long-term studies are considered, unless a procedure to actively compensate for degradation is provided. In this short report, we describe the use and fabrication of arrays of 120 planar microelectrodes (MEAs) of sputtered Iridium Oxide (IrOx). The effective surface area of individual microelectrodes is significantly increased using electrochemical activation, a procedure that may also be employed to restore the properties of the electrodes as required. The electrode activation results in a very low interface impedance, especially in the lower frequency domain, which was characterized by impedance spectroscopy. The increase in the roughness of the microelectrodes surface was imaged using digital holographic microscopy and electron microscopy. Aging of the activated electrodes was also investigated, comparing storage in saline with storage in air. Demonstration of concept was achieved by recording multiple single-unit spike activity in acute brain slice preparations of rat neocortex. Data suggests that extracellular recording of action potentials can be achieved with planar IrOx MEAs with good signal-to-noise ratios.
substrate microelectrodes, extracellular recordings, electrophysiology, impedance spectroscopy, neurons, cortex
1662-6443
1-7
Gawad, Shady
98f746a7-4bcc-42bb-a450-dafda85be29c
Morgan, H.
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Guigliano, M.
b3f6d22c-0035-44c0-ac9c-9d60caf401eb
Heuschkel, M.O.
4ea1836c-48a0-4f1e-a3eb-1c2479600129
Gawad, Shady
98f746a7-4bcc-42bb-a450-dafda85be29c
Morgan, H.
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Guigliano, M.
b3f6d22c-0035-44c0-ac9c-9d60caf401eb
Heuschkel, M.O.
4ea1836c-48a0-4f1e-a3eb-1c2479600129

Gawad, Shady, Morgan, H., Guigliano, M. and Heuschkel, M.O. (2009) Substrate arrays of iridium oxide microelectrodes for in vitro neuronal interfacing. Frontiers in Neuroengineering, 2 (1), 1-7.

Record type: Article

Abstract

The design of novel bidirectional interfaces for in vivo and in vitro nervous systems is an important step towards future functional neuroprosthetics. Small electrodes, structures and devices are necessary to achieve high-resolution and target-selectivity during stimulation and recording of neuronal networks, while significant charge transfer and large signal-to-noise ratio are required for accurate time resolution. In addition, the physical properties of the interface should remain stable across time, especially when chronic in vivo applications or in vitro long-term studies are considered, unless a procedure to actively compensate for degradation is provided. In this short report, we describe the use and fabrication of arrays of 120 planar microelectrodes (MEAs) of sputtered Iridium Oxide (IrOx). The effective surface area of individual microelectrodes is significantly increased using electrochemical activation, a procedure that may also be employed to restore the properties of the electrodes as required. The electrode activation results in a very low interface impedance, especially in the lower frequency domain, which was characterized by impedance spectroscopy. The increase in the roughness of the microelectrodes surface was imaged using digital holographic microscopy and electron microscopy. Aging of the activated electrodes was also investigated, comparing storage in saline with storage in air. Demonstration of concept was achieved by recording multiple single-unit spike activity in acute brain slice preparations of rat neocortex. Data suggests that extracellular recording of action potentials can be achieved with planar IrOx MEAs with good signal-to-noise ratios.

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Accepted/In Press date: 15 January 2009
Published date: 22 January 2009
Keywords: substrate microelectrodes, extracellular recordings, electrophysiology, impedance spectroscopy, neurons, cortex
Organisations: Electronics & Computer Science

Identifiers

Local EPrints ID: 355449
URI: https://eprints.soton.ac.uk/id/eprint/355449
ISSN: 1662-6443
PURE UUID: c1108cec-8928-4d38-9637-c71f274cf8c6
ORCID for H. Morgan: ORCID iD orcid.org/0000-0003-4850-5676

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Date deposited: 27 Aug 2013 15:28
Last modified: 06 Jun 2018 12:45

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