Thin film platinum cuff electrodes for neurostimulation: in vitro approach of safe neurostimulation parameters.
Thin film technology takes more and more importance in the development of biomedical devices dedicated to functional neurostimulation. Our research about the design of implant neurostimulating electrode is oriented toward thin film cuff electrodes based on a polyimide substrate covered by a chromium/gold/Pt film. The chromium/gold sputtered film serves as adhesion layer and current collector whereas platinum acts as an electrochemical actuator. The electrode surface has been designed to obey safe stimulation criteria (i.e. chemically inert noble metal, low electrode-electrolyte impedance, high electrochemical reversibility, high corrosion stability). The electrochemical behaviour of such platinum electrodes has been assessed and compared to a foil of platinum. Extensive in vitro characterisations of the both electrode types were carried out using AFM, SEM and electrochemical techniques. The role of enhanced surface roughness enabling high double layer capacitances to be achieved was clearly highlighted. The obtained results are discussed, with particular reference to thin film electrodes stability under in vitro electrical stimulation in NaCl 0.9% (physiological serum). Therefore, these thin film devices showed reversible PtOH formation and decomposition making them potentially attractive for the fabrication of implant stimulation cuff electrodes.
Mailley
Sophie
S
Northern Ireland Bio-Engineering Centre, University of Ulster at Jordanstown, Shore Road, Newtownabbey, Co. Antrim, Northern Ireland, BT37 OQB, UK.
Hyland
Marc
M
Mailley
Pascal
P
McLaughlin
James A
JA
McAdams
Eric T
ET
D001826:Body Fluids / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017097:Electric Impedance; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004563:Electrochemistry / Q000379:methods; D004567:Electrodes, Implanted; D004869:Equipment Safety / Q000379:methods*; D006801:Humans; D008422:Materials Testing / Q000379:methods; D010525:Peripheral Nerves / Q000502:physiology; D010984:Platinum / Q000737:chemistry*; D019736:Prostheses and Implants; D013499:Surface Properties
D020099:Coated Materials, Biocompatible; D010984:Platinum