Electrical stimulation causes rapid changes in electrode impedance of cell-covered electrodes

Carrie Newbold*, Rachael Richardson, Rodney Millard, Peter Seligman, Robert Cowan, Robert Shepherd

*Corresponding author for this work

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Animal and clinical observations of a reduction in electrode impedance following electrical stimulation encouraged the development of an in vitro model of the electrode-tissue interface. This model was used previously to show an increase in impedance with cell and protein cover over electrodes. In this paper, the model was used to assess the changes in electrode impedance and cell cover following application of a charge-balanced biphasic current pulse train. Following stimulation, a large and rapid drop in total impedance (Zt) and access resistance (Ra) occurred. The magnitude of this impedance change was dependent on the current amplitude used, with a linear relationship determined between Ra and the resulting cell cover over the electrodes. The changes in impedance due to stimulation were shown to be transitory, with impedance returning to pre-stimulation levels several hours after cessation of stimulation. A loss of cells over the electrode surface was observed immediately after stimulation, suggesting that the level of stimulation applied was creating localized changes to cell adhesion. Similar changes in electrode impedance were observed for in vivo and in vitro work, thus helping to verify the in vitro model, although the underlying mechanisms may differ. A change in the porosity of the cellular layer was proposed to explain the alterations in electrode impedance in vitro. These in vitro studies provide insight into the possible mechanisms occurring at the electrode-tissue interface in association with electrical stimulation.

Original languageEnglish
Article number036029
Pages (from-to)1-13
Number of pages13
JournalJournal of Neural Engineering
Volume8
Issue number3
DOIs
Publication statusPublished - Jun 2011
Externally publishedYes

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