Intrinsic activation of iridium electrodes over a wireless link.

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference (2013-02-01)
Zhe Hu, Philip Troyk, Glenn DeMichele, Kevin Kayvani, Sungjae Suh
ABSTRACT

Activated Iridium Oxide Film (AIROF) microelectrodes are regarded as advantage for stimulation of neural tissue owing to their superior charge injection capabilities, as compared to other noble-metal based electrodes. Including AIROF electrodes within an implantable neural stimulator can be challenging since the stimulator fabrication steps often involve elevated temperatures at which the AIROF can be damaged. In this work, a wireless neural stimulator application-specific-integrated-circuit (ASIC) was used to intrinsically activate iridium microelectrodes. This intrinsic activation allows for the growth of the AIROF as the final assembly step after the entire device is assembled, thus avoiding stress on the AIROF. Since a typical neural stimulator is essentially a current-controlled driver with voltage compliance limits, its output waveform can be tuned to match the traditional voltage pulsing/ramp activation waveform. Here the feasibility of the current driven activation of iridium electrodes, over a wireless link, is demonstrated.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Iridium(IV) oxide, 99.9% trace metals basis
Sigma-Aldrich
Iridium, powder, 99.9% trace metals basis
Sigma-Aldrich
Iridium, wire, diam. 0.15 mm, 99.9% trace metals basis
Sigma-Aldrich
Iridium, evaporation slug, diam. × L 0.6 cm × 1.2 cm, 99.9% trace metals basis
Sigma-Aldrich
Iridium, black, powder, −200 mesh, ≥99% trace metals basis
Sigma-Aldrich
Iridium, foil, thickness 0.25 mm, 99.9% trace metals basis