Sputtered iridium oxide films (SIROFs) for low-impedance neural stimulation and recording electrodes

Cogan, Stuart F.; Plante, Timothy D.; Ehrlich, J.

doi:10.1109/iembs.2004.1404158

Cited by 96 publications

(81 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar approach using non-toxic components during film formation has been introduced by Zhou 2005, known as Pt gray, however the roughness was found substantially lower compared to Pt-black [20]. Cui et al [21] and Cogan et al [22] demonstrated successfully the reduction of the electrode impedance using either conducting M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT polymers as e.g. poly(3,4-ethylenedioxythiophene) (PEDOT) or using Iridium Oxide (IrOx) targeting both the chemical and the topographical approach to improve the electrode performance.…”

Section: Introductionmentioning

confidence: 97%

Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes

2015

View full text Add to dashboard Cite

Micro-sized electrodes are essential for highly sensitive communication at the neural interface with superior spatial resolution. However, such small electrodes inevitably suffer from high electrical impedance and thus high levels of thermal noise deteriorating the signal to noise ratio. In order to overcome this problem, a nanostructured Pt-coating was introduced as add-on functionalization for impedance reduction of small electrodes. In comparison to platinum black deposition, all used chemicals in the deposition process are free from cytotoxic components. The grass-like nanostructure was found to reduce the impedance by almost two orders of magnitude compared to untreated samples which was lower than what could be achieved with conventional electrode coatings like IrOx or PEDOT. The realization of the Pt-grass coating is performed via a simple electrochemical process which can be applied to virtually any possible electrode type and accordingly shows potential as a universal impedance reduction strategy. Elution tests revealed non-toxicity of the Pt-grass and the coating was found to exhibit strong adhesion to the metallized substrate.

show abstract

Section: Introductionmentioning

confidence: 97%

Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes

2015

View full text Add to dashboard Cite

show abstract

“…One of the popular electrode materials, sputtered iridium oxide (SIROF), can deliver up to 5 mC/cm 2 via an electrode of 30 m in diameter, with the use of 0.5-ms pulses (Cogan et al 2004). These settings correspond to the maximum current of 70 A, which is 16 -175 times higher than the stimulation lower threshold at this pulse duration, and can significantly exceed the stimulation upper threshold.…”

Section: Computational Modeling Of Extracellular Stimulationmentioning

confidence: 99%

“…The strength-duration relationship defines for a given pulse duration the minimum stimulus strength, or stimulation threshold, above which an action potential (AP) is generated. It is generally assumed that a neuron will elicit AP at any stimulus strength above the threshold, and the upper limit is defined only by the cellular damage (Butterwick et al 2007;McCreery et al 1990) or by the limits of irreversible electrochemistry on stimulating electrode (Brummer and Turner 1977;Cogan et al 2004).…”

mentioning

confidence: 99%

Upper threshold of extracellular neural stimulation

Boinagrov

Pangratz-Fuehrer

Suh

et al. 2012

Journal of Neurophysiology

View full text Add to dashboard Cite

It is well known that spiking neurons can produce action potentials in response to extracellular stimulation above certain threshold. It is widely assumed that there is no upper limit to somatic stimulation, except for cellular or electrode damage. Here we demonstrate that there is an upper stimulation threshold, above which no action potential can be elicited, and it is below the threshold of cellular damage. Existence of this upper stimulation threshold was confirmed in retinal ganglion cells (RGCs) at pulse durations ranging from 5 to 500 μs. The ratio of the upper to lower stimulation thresholds varied typically from 1.7 to 7.6, depending on pulse duration. Computational modeling of extracellular RGC stimulation explained the upper limit by sodium current reversal on the depolarized side of the cell membrane. This was further confirmed by experiments in the medium with a low concentration of sodium. The limited width of the stimulation window may have important implications in design of the electro-neural interfaces, including neural prosthetics

show abstract

“…9 However, PEDOT and other conjugated polymers, including polypyrrole and polyaniline, are non-biodegradable and brittle. 10 In certain tissues, such as the heart, conjugated polymers could cause adverse immune responses upon implantation, as the ischemic myocardium is a hostile environment where inflammatory responses can perpetuate the scarring. 11 .…”

Section: Introductionmentioning

confidence: 99%

Electroactive biomimetic collagen-silver nanowire composite scaffolds

Wickham

Vagin²,

Khalaf

et al. 2016

Nanoscale

View full text Add to dashboard Cite

Electroactive biomaterials are used in a number of applications, including scaffolds for neural and cardiac regeneration. Most electrodes and conductive scaffolds for tissue regeneration are based on synthetic materials that have limited biocompatibility and often display a large mismatch in mechanical properties with the surrounding tissue. In this work we have developed a nanocomposite material prepared from self-assembled collagen and silver nanowires (AgNW) that display electrical properties analogous to electrodes used in the clinic. The AgNW concentration of the nanocomposites was optimized to stimulate proliferation of isolated embryonic cardiomyocytes. In addition, the AgNWs renders the nanocomposites antimicrobial against both Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis.The mechanical properties of the nanocomposites were further characterized in physiological conditions and showed a dynamic modulus within the lower kPa range, suitable for embryonic cardiomyocyte proliferation. An in depth electrochemical analysis of the materials in the wet state showed a charge storage capacity of 12.28 mC cm -2 , and charge injection capacity of 0.33 mC cm -2 , comparable to electrode materials, such as iridium oxide and polypyrrole, currently used for electrical stimulation of tissues. The collagen/AgNW composites are thus multifunctional structural scaffolds that promote embryonic cardiomyocyte function, with the ability to store and inject charges, along with providing antimicrobial resistance.3

show abstract

Sputtered iridium oxide films (SIROFs) for low-impedance neural stimulation and recording electrodes

Cited by 96 publications

References 11 publications

Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes

Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes

Upper threshold of extracellular neural stimulation

Electroactive biomimetic collagen-silver nanowire composite scaffolds

Contact Info

Product

Resources

About