Platinum for neural stimulation: voltammetry considerations

The underlying cause of electrical stimulation-induced tissue trauma is debated. Our focus has been to study effects of generating electrochemical by-products at the electrode-electrolyte interface, using the pulse-clamp technique coupled with voltammetry to analyze charge transfer. The platinum-H(2...

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Bibliographic Details
Published in:Journal of neural engineering 2010-04, Vol.7 (2), p.026005-26005
Main Authors: Hudak, E M, Mortimer, J T, Martin, H B
Format: Article
Language:English
Subjects:
Animals
Electric Stimulation - instrumentation
Electrodes
Electrolytes - chemistry
Models, Neurological
Neurons - chemistry
Oxidation-Reduction
Phosphates - chemistry
Platinum Compounds - chemistry
Silver Compounds - chemistry
Sodium Chloride - chemistry
Sulfuric Acids - chemistry
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Summary:The underlying cause of electrical stimulation-induced tissue trauma is debated. Our focus has been to study effects of generating electrochemical by-products at the electrode-electrolyte interface, using the pulse-clamp technique coupled with voltammetry to analyze charge transfer. The platinum-H(2)SO(4) system has been a standard for analyzing electrochemistry on platinum-stimulating electrodes, even though the chemical differences between H(2)SO(4) and the living body are obvious. Experiments were designed to determine whether phosphate-buffered saline (PBS) could serve as a more accurate emulation of living tissue. It had been rumored that platinum's performance in PBS deviates from that in H(2)SO(4) at larger potentials. Voltammetry in PBS was performed in two potential ranges. In a conventional potential range (-0.6 V to +0.9 V versus Ag/AgCl), characteristic peaks appear very similar to published voltammograms of platinum in H(2)SO(4). However, in an extended range (-1.0 V to +1.7 V versus Ag/AgCl), platinum exhibited additional electrochemical activity: one oxidation peak and two reduction peaks. Therefore, voltammetry was performed in NaCl and a sodium phosphate mixture (i.e. PBS components) to separate their activity. The altered electrochemical performance of platinum in PBS suggests that certain reactions on platinum at potentials outside the water window will not reflect what happens in vivo.
ISSN:1741-2552
1741-2560
1741-2552
DOI:10.1088/1741-2560/7/2/026005