Journal article

Electrochemical and biological characterization of thin-film platinum-iridium alloy electrode coatings: a chronic in vivo study

Ashley N Dalrymple, Mario Huynh, Bryony A Nayagam, Curtis D Lee, Greg R Weiland, Artin Petrossians, J John, III Whalen, James B Fallon, Robert K Shepherd



OBJECTIVE: To evaluate the electrochemical properties, biological response, and surface characterization of an electrodeposited Platinum-Iridium (Pt-Ir) electrode coating on cochlear implants subjected to chronic stimulation in vivo. APPROACH: Electrochemical impedance spectroscopy (EIS), charge storage capacity (CSC), charge injection limit (CIL), and voltage transient (VT) impedance were measured bench-top before and after implant and in vivo. Coated Pt-Ir and uncoated Pt electrode arrays were implanted into cochlea of normal hearing rats and stimulated for ∼4 h d, 5 d week-1 for 5 weeks at levels within the normal clinical range. Neural function was monitored using electrically-evoked aud..

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Awarded by NHMRC of the Australian Government

Funding Acknowledgements

This work was funded by the NHMRC of the Australian Government (APP1122055) and the Garnett Passe and Rodney Williams Memorial Foundation for which we are most grateful. The Bionics Institute acknowledges support of the Victorian Government through Operational Infrastructure Support Program. We thank Drs A Thompson and T Hyakumara, C McGowan, and R Thomas and the electrode fabrication team from the Bionics Institute; the staff of EMSU, St Vincent's Hospital Melbourne for animal care; and R Curtain and the SEM Facility at Bio21, University of Melbourne for their technical assistance. Platinum Group Coatings (PGC) acknowledges the support of the Pasadena Bioscience Collaborative and thanks to J Sharkey for preparing test samples.