Investigating the Interfacial Properties of Electrochemically Roughened Platinum Electrodes for Neural Stimulation

Weremfo, Alexander; Carter, Paul; Hibbert, David Brynn; Zhao, Chuan

doi:10.1021/la504876n

Cited by 45 publications

(46 citation statements)

References 37 publications

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“…This is due to platinum's high level of pseudocapacity (50-150 μC/cm 2 ) [Brummer and Turner, 1977], which can be further enhanced by increasing the surface area/electrode size ratio via electrochemical roughening [Weremfo et al, 2015]. Pseudocapacity is a property of some metals where a faradaic electron transfer occurs but the product remains bound to the electrode surface, allowing for the reversal of the reaction for AC directions.…”

Section: Multifunctional Device Designmentioning

confidence: 99%

Bioelectric Medicine and Devices for the Treatment of Spinal Cord Injury

Torregrosa¹,

Koppes²

2016

Cells Tissues Organs

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Recovery of motor control is paramount for patients living with paralysis following spinal cord injury (SCI). While a cure or regenerative intervention remains on the horizon for the treatment of SCI, a number of neuroprosthetic devices have been employed to treat and mitigate the symptoms of paralysis associated with injuries to the spinal column and associated comorbidities. The recent success of epidural stimulation to restore voluntary motor function in the lower limbs of a small cohort of patients has breathed new life into the promise of electric-based medicine. Recently, a number of new organic and inorganic electronic devices have been developed for brain-computer interfaces to bypass the injury, for neurorehabilitation, bladder and bowel control, and the restoration of motor or sensory control. Herein, we discuss the recent advances in neuroprosthetic devices for treating SCI and highlight future design needs for closed-loop device systems.

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Section: Multifunctional Device Designmentioning

confidence: 99%

Bioelectric Medicine and Devices for the Treatment of Spinal Cord Injury

Torregrosa¹,

Koppes²

2016

Cells Tissues Organs

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“…[8] Pt has been roughened using a repetitive square wave potential cycle at 1 kHz involving the oxidation of the surface and its subsequent reduction for use as electrodes for neural stimulation. [9] Highly active copper surfaces have also been produced via the reduction of electrochemically grown Cu (OH) 2 films. [10] In addition, copper nanoparticles have been produced via reduction of CuCl powder in an ionic liquid to produce particles of ,10 nm in diameter.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Restructuring of Copper Surfaces Using Organic Additives and Its Effect on the Electrocatalytic Reduction of Nitrate Ions

Balkis

O’Mullane

2015

Aust. J. Chem.

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This work describes the fabrication of nanostructured copper electrodes using a simple potential cycling protocol that involves oxidation and reduction of the surface in an alkaline solution. It was found that the inclusion of additives, such as benzyl alcohol and phenylacetic acid, has a profound effect on the surface oxidation process and the subsequent reduction of these oxides. This results in not only a morphology change, but also affects the electrocatalytic performance of the electrode for the reduction of nitrate ions. In all cases, the electrocatalytic performance of the restructured electrodes was significantly enhanced compared with the unmodified electrode. The most promising material was formed when phenylacetic acid was used as the additive. In addition, the reduction of residual oxides on the surface after the modification procedure to expose freshly active reaction sites on the surface before nitrate reduction was found to be a significant factor in dictating the overall electrocatalytic activity. It is envisaged that this approach offers an interesting way to fabricate other nanostructured electrode surfaces.

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“…19 The method was later developed for SERS on thick Pt samples. 20 Additionally, platinum, 10,11,20 gold, 21 silver 19 and palladium 22 thick metal (wire and foil) electrodes can be roughened electrochemically with application of bipolar pulses that form oxides during anodic pulse and etch away those oxides during cathodic pulse. Roughening via electrochemical etching is attractive because it yields large increases in surface area with low cost, low toxicity, and well controlled processes.…”

mentioning

confidence: 99%

“…10,11 Roughening with a series of oxidation-reduction voltage pulses increased the active surface area up to 75x 10 and was recently further optimized to achieve a 250x increase in surface area 11 and led to increase in charge injection limit up to 1000 μC/cm 2 (from 50−150 μC/cm 2 for untreated Pt). 11 The newest generation of neural interfaces requires further miniaturization to the microscale, with electrode surface areas of ≤8000 μm 2 instead of larger macroscale electrodes (>49,000 μm 2 ). Densely-packed microelectrodes in a region are preferred over a single macroelectrode to increase resolution and selectivity in both stimulating and recording electrical and chemical signals in neural interfaces of the future.…”

mentioning

confidence: 99%

“…This reduction in geometric area can compromise important electroactive characteristics of the electrodes used for a wide range of biomedical applications. These compromised characteristics include 1) diminished charge that can be safely delivered by the electrode during neuro-stimulation, 11 2) undesirable increases in impedance for recording electrodes, 18,23 and…”

mentioning

confidence: 99%

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Electrochemical Roughening of Thin-Film Platinum for Neural Probe Arrays and Biosensing Applications

Ivanovskaya

Belle

Yorita

et al. 2018

J. Electrochem. Soc.

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We report a method for electrochemical roughening of thin-film platinum (Pt) electrodes that increases active surface area, decreases electrode impedance, increases charge injection capacity, increases sensitivity of biosensors and improves adhesion of electrochemically deposited films. First, a well-established technique for electrochemical roughening of thick Pt electrodes (wires and foils) by oxidation-reduction pulses was modified for use on thin-film Pt. Optimal roughening of thin-film Pt electrodes with this established protocol in a sulfuric acid solution was found to occur at about four times lower frequency than that typically used for thick Pt. This modification in established procedure created a 21x surface area increase but showed nanoscale cracks from inter-grain Pt dissolution that compromised film integrity. A crack free surface with Pt nanocrystal re-deposition (20-30 nm in size) and higher enhancement in surface area (44x) was obtained when the electrolyte was switched to a non-adsorbing perchloric acid solution. These electrochemically roughened electrodes have charge injection limits comparable to titanium nitride and just below carbon nanotube-based materials. Roughened microelectrodes showed a 2.8x increase in sensitivity to hydrogen peroxide detection, indicative of improved enzymatic biosensor performance. Platinum iridium and iridium oxide coatings on these roughened surfaces showed an improvement in adhesion. Microfabrication techniques have enabled the bulk fabrication of robust, reproducible neural interfaces. 1,2 These neural interfaces typically contain conductive metal electrodes that serve as the 'interface' between the device and the tissue. 3 When microfabricated, these electrodes are typically thin films of metal, a few hundred nanometers thick and recent advances show these interfaces to be constructed on thin flexible substrates, further improving the ability of electrodes to interface with tissue. 4-7 While these thin film electrodes generally act very similar to bulk metal found in non-microfabricated neural interfaces, they can be more delicate than bulk metal, 8 especially when fabricated on a flexible substrate. Both bulk and thin film metal interfaces demand highest performance to ensure that they can properly interface with tissue without causing damage to the tissue. Often, electrode surface modifications are needed to enhance performance.Enhanced electrode performance can be accomplished by 1) roughening the electrode surface to increase the effective surface area; 9-11 or, 2) depositing a thin-film coating of a material with enhanced electrochemical activity. [12][13][14][15] When depositing a different thin film electroactive material over the electrode to improve performance, there is often poor adhesion of the deposited film to the electrode surface. 9,16 Poor film adhesion compromises the mechanical robustness of an implantable device which may result in immediate delamination or decreased lifetime of the electrode upon implantation, ultimately deteriorating sens...

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Investigating the Interfacial Properties of Electrochemically Roughened Platinum Electrodes for Neural Stimulation

Cited by 45 publications

References 37 publications

Bioelectric Medicine and Devices for the Treatment of Spinal Cord Injury

Bioelectric Medicine and Devices for the Treatment of Spinal Cord Injury

Electrochemical Restructuring of Copper Surfaces Using Organic Additives and Its Effect on the Electrocatalytic Reduction of Nitrate Ions

Electrochemical Roughening of Thin-Film Platinum for Neural Probe Arrays and Biosensing Applications

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