Low-Impedance, High Surface Area Pt-Ir Electrodeposited on Cochlear Implant Electrodes

Lee, Curtis D.; Hudak, Eric M; Whalen, John J.; Petrossians, Artin; Weiland, James D.

doi:10.1149/2.0031812jes

Cited by 28 publications

(27 citation statements)

References 14 publications

(16 reference statements)

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“…Functional electrostimulation (FES) is a technique used to treat dorsal spine injuries, sensorial problems, as well as neurological problems. Applications of functional electrostimulation include restoration of hand function for individuals with cervical level spinal cord injury (SCI) [5], restoration of vision to the blind by using an array of electrodes attached to the retina [6,7], treatment of hearing problems [8,9], and deep brain stimulation for neural problems including Parkinson’s disease [10], involuntary movements, and psychiatric diseases such as depression and obsessive compulsive disorder [11,12].…”

Section: Introductionmentioning

confidence: 99%

Application of a Novel Measurement Setup for Characterization of Graphene Microelectrodes and a Comparative Study of Variables Influencing Charge Injection Limits of Implantable Microelectrodes

Cisnal

Ihmig

Fraile

et al. 2019

Sensors

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Depending on their use, electrodes must have a certain size and design so as not to compromise their electrical characteristics. It is fundamental to be aware of all dependences on external factors that vary the electrochemical characteristics of the electrodes. When using implantable electrodes, the maximum charge injection capacity (CIC) is the total amount of charge that can be injected into the tissue in a reversible way. It is fundamental to know the relations between the characteristics of the microelectrode itself and its maximum CIC in order to develop microelectrodes that will be used in biomedical applications. CIC is a very complex measure that depends on many factors: material, size (geometric and effectiveness area), and shape of the implantable microelectrode and long-term behavior, composition, and temperature of the electrolyte. In this paper, our previously proposed measurement setup and automated calculation method are used to characterize a graphene microelectrode and to measure the behavior of a set of microelectrodes that have been developed in the Fraunhofer Institute for Biomedical Engineering (IBMT) labs. We provide an electrochemical evaluation of CIC for these microelectrodes by examining the role of the following variables: pulse width of the stimulation signal, electrode geometry and size, roughness factor, solution, and long-term behavior. We hope the results presented in this paper will be useful for future studies and for the manufacture of advanced implantable microelectrodes.

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Section: Introductionmentioning

confidence: 99%

Application of a Novel Measurement Setup for Characterization of Graphene Microelectrodes and a Comparative Study of Variables Influencing Charge Injection Limits of Implantable Microelectrodes

Cisnal

Ihmig

Fraile

et al. 2019

Sensors

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“…The general solution of the ODE was obtained by introducing expressions (25) and (26) in (24). Then, using the initial condition, the value of was determined; obtaining in this way the unique solution of the Cauchy problem.…”

Section: Solution Of the Cauchy Problemmentioning

confidence: 99%

Theoretical Determination of the Stabilization Time in Galvanostatic EIS Measurements: The Simplified Randles Cell

Giner-Sanz¹,

Ortega²,

García-Gabaldón³

et al. 2018

J. Electrochem. Soc.

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Usually, EIS measurements are performed in 2 steps: a stabilization step followed by an acquisition step. The first is necessary in order to ensure that the impedance is determined when the system has reached its stationary state. In this work, a theoretical framework is proposed for estimating the required stabilization time for EIS measurements. Here, it was applied to the simplest case: the simplified Randles cell. In order to calculate the required stabilization time for performing EIS measurements, a theoretical dynamic model of a Randles cell under galvanostatic sinusoidal perturbation was developed. The proposed model can be used to estimate, from a theoretical point of view, the required stabilization time for performing EIS measurements in a Randles-like system. Even though, this work focuses on the simplest case, the developed theoretical framework can be applied to any system, however complex it may be.

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“…Electrodeposited platinum-iridium coating has demonstrated its ability to record single units through microelectrodes ( Cassar et al, 2019 ), as well as deliver charge through relatively large cochlear electrodes both in vitro ( Lee et al, 2018 ; Dalrymple et al, 2019 ) and in vivo ( Dalrymple et al, 2020 ). Darymple et al ( Dalrymple et al, 2019 ) compared EPIC electrode to PEDOT and Graphene Oxide in an accelerated aging electrochemistry experiment in saline.…”

Section: Introductionmentioning

confidence: 99%

Stimulation and Recording of the Hippocampus Using the Same Pt-Ir Coated Microelectrodes

Elyahoodayan

Jiang

Lee³

et al. 2021

Front. Neurosci.

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Same-electrode stimulation and recording with high spatial resolution, signal quality, and power efficiency is highly desirable in neuroscience and neural engineering. High spatial resolution and signal-to-noise ratio is necessary for obtaining unitary activities and delivering focal stimulations. Power efficiency is critical for battery-operated implantable neural interfaces. This study demonstrates the capability of recording single units as well as evoked potentials in response to a wide range of electrochemically safe stimulation pulses through high-resolution microelectrodes coated with co-deposition of Pt-Ir. It also compares signal-to-noise ratio, single unit activity, and power efficiencies between Pt-Ir coated and uncoated microelectrodes. To enable stimulation and recording with the same microelectrodes, microelectrode arrays were treated with electrodeposited platinum-iridium coating (EPIC) and tested in the CA1 cell body layer of rat hippocampi. The electrodes’ ability to (1) inject a large range of electrochemically reversable stimulation pulses to the tissue, and (2) record evoked potentials and single unit activities were quantitively assessed over an acute time period. Compared to uncoated electrodes, EPIC electrodes recorded signals with higher signal-to-noise ratios (coated: 9.77 ± 1.95 dB; uncoated: 1.95 ± 0.40 dB) and generated lower voltages (coated: 100 mV; uncoated: 650 mV) for a given stimulus (5 μA). The improved performance corresponded to lower energy consumptions and electrochemically safe stimulation above 5 μA (>0.38 mC/cm2), which enabled elicitation of field excitatory post synaptic potentials and population spikes. Spontaneous single unit activities were also modulated by varying stimulation intensities and monitored through the same electrodes. This work represents an example of stimulation and recording single unit activities from the same microelectrode, which provides a powerful tool for monitoring and manipulating neural circuits at the single neuron level.

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Low-Impedance, High Surface Area Pt-Ir Electrodeposited on Cochlear Implant Electrodes

Cited by 28 publications

References 14 publications

Application of a Novel Measurement Setup for Characterization of Graphene Microelectrodes and a Comparative Study of Variables Influencing Charge Injection Limits of Implantable Microelectrodes

Application of a Novel Measurement Setup for Characterization of Graphene Microelectrodes and a Comparative Study of Variables Influencing Charge Injection Limits of Implantable Microelectrodes

Theoretical Determination of the Stabilization Time in Galvanostatic EIS Measurements: The Simplified Randles Cell

Stimulation and Recording of the Hippocampus Using the Same Pt-Ir Coated Microelectrodes

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