Chronic Electrochemical Investigation of Titanium Nitride Stimulation Electrodes in vivo

Abstract

For neural prostheses to be successful, good performance of neurostimulation electrodes is important. An important aspect of this is electrochemical stability and corrosion resistance. The electrochemical performance of 4 thin film titanium nitride (TiN) electrodes is investigated in a porcine animal model. In vivo impedance measurements have been made for 3 months to investigate the electrode-tissue interface and to monitor tissue resistance in vivo. The tissue resistance was low in the first week, after which it increased and stabilized. After 50 days, a dramatic change is observed in the electrode-tissue interface; charge is transferred via faradic instead of capacitive pathways. This is likely due to anodic oxidation of the TiN surface. This was not reversed, but no signs of further oxidation were observed. Neither the tissue nor the electrode appeared damaged after explantation.KeywordsDeep Brain StimulationTitanium NitrideDeep Brain Stimulation ElectrodeNeural ProsthesisElectrochemical Impedance SpecThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.