In vitro and In vivo comparison of the charge injection capacity of platinum macroelectrodes

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dc.contributor.authorLeung, Ronald
dc.contributor.authorShivdasani, Mohit
dc.contributor.authorNayagam, David
dc.contributor.authorShepherd, Robert
dc.date.accessioned2015-03-02T03:50:43Z
dc.date.available2015-03-02T03:50:43Z
dc.date.issued2015-03
dc.description.abstractPlatinum (Pt) is the most commonly used metal for stimulating electrodes. This study aims to determine the amount of charge that can be delivered without causing irreversible electrochemical reactions (charge injection capacity, Q inj) of Pt macroelectrodes (geometric surface area >0.001 cm(2)) in vitro and in vivo using voltage transient measurements. Pt macroelectrodes were stimulated with biphasic charge-balanced cathodic-first constant-current pulses in phosphate buffered saline. Potential excursions were measured (versus Ag/AgCl electrode) and used to determine Qinj. The in vitro Qinj were compared to those measured in vivo following: acute and chronic implantation close to the retina; chronic intracochlear implantation; and acute subdural implantation, in the cat. Qinj increased with pulsewidth from 35 to 54 μC/cm(2) for respective pulse widths of 100 to 3200 μs per phase in vitro. Qinj was significantly less in vivo. There was no significant difference in Qinj between acutely (3.84 to 16.6 μC/cm(2) with pulsewidths of 100 to 3200 μs) and chronically (6.99 to 15.8 μC/cm(2) with pulsewidths of 200 to 3200 μs) implanted suprachoroidal electrodes. Intracochlear Qinj was not different to suprachoroidal Qinj, while subdural Qinj was significantly less than the suprachoroidal Q inj (p < 0.05). These results have important implications in providing guidelines on Qinj for the safe use of Pt stimulating macroelectrodes and question the relevance of measuring Qinj in vivo using voltage transients.en_US
dc.description.sponsorshipThis work was supported by the Australian Research Council through its Special Research Initiative in Bionic Vision Science and Technology grant to Bionic Vision Australia. The work of R. T. Leung was supported by the Harold Mitchell Foundation.en_US
dc.identifier.citationLeung, R. T., Shivdasani, M. N., Nayagam, D. A. X., & Shepherd, R. K. (2015). In vitro and In vivo comparison of the charge injection capacity of platinum macroelectrodes. IEEE Trans Biomed Eng, 62(3), 849-85en_US
dc.identifier.urihttp://repository.bionicsinstitute.org:8080/handle/123456789/114
dc.language.isoenen_US
dc.publisherIEEEen_US
dc.subjectbiomedical electrodesen_US
dc.subjectblindnessen_US
dc.subjectelectrical stimulationen_US
dc.subjectelectrochemical processesen_US
dc.subjectimplantable biomedical devicesen_US
dc.subjectin vitroen_US
dc.subjectin vivoen_US
dc.subjectneural prosthesisen_US
dc.subjectvisual prosthesisen_US
dc.titleIn vitro and In vivo comparison of the charge injection capacity of platinum macroelectrodesen_US
dc.typeArticleen_US
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