title: Electrochemical and Electrophysiological Performance of Platinum Electrodes Within the Ninety-Nine-Electrode Stimulating Nerve Cuff.
abstract: The trend in neural prostheses using selective nerve stimulation for electrical stimulation therapies is headed toward single-part systems having a large number of working electrodes (WEs), each of which selectively stimulate neural tissue or record neural response (NR). The present article reviews the electrochemical and electrophysiological performance of platinum WE within a ninety-nine-electrode spiral cuff for selective nerve stimulation and recording of peripheral nerves, with a focus on the vagus nerve (VN). The electrochemical properties of the WE were studied in vitro using the electrochemical impedance spectroscopy (EIS) technique. The equivalent circuit model (ECM) of the interface between the WE and neural tissue was extracted from the EIS data and simulated in the time domain using a preset current stimulus. Electrophysiological performance of in-space and fiber-type highly selective vagus nerve stimulation (VNS) was tested using an isolated segment of a porcine VN and carotid artery as a reference. A quasitrapezoidal current-controlled pulse (stimulus) was applied to the VN or arterial segment using an appointed group of three electrodes (triplet). The triplet and stimulus were configured to predominantly stimulate B-fibers and minimize the stimulation of A-fibers. The EIS results revealed capacitive charge transfer predominance, which is a highly desirable property. Electrophysiological performance testing indicated the potential existence of certain parameters and waveforms of the stimulus for which the contribution of the A-fibers to the NR decreased slightly and that of the B-fibers increased slightly. Findings show that the design of the stimulating electrodes, based on the EIS and ECM results, could act as a useful tool for nerve cuff development.
authors.affiliation: Center for Implantable Technology and Sensors, ITIS d. o. o. Ljubljana, Ljubljana, Slovenia.
authors.forename: Polona
authors.initials: P
authors.lastname: Pečlin
authors.affiliation: Center for Implantable Technology and Sensors, ITIS d. o. o. Ljubljana, Ljubljana, Slovenia.
authors.forename: Andraž
authors.initials: A
authors.lastname: Mehle
authors.affiliation: Department of Materials and Metallurgy, Faculty of Natural Sciences and Engineering, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Blaž
authors.initials: B
authors.lastname: Karpe
authors.affiliation: Center for Implantable Technology and Sensors, ITIS d. o. o. Ljubljana, Ljubljana, Slovenia.
authors.forename: Janez
authors.initials: J
authors.lastname: Rozman
mesh_terms: D058266:Dielectric Spectroscopy; D004563:Electrochemistry; D004566:Electrodes; D004567:Electrodes, Implanted; D055724:Electrophysiological Phenomena / Q000502:physiology; D006801:Humans; D010525:Peripheral Nerves / Q000503:physiopathology; D010984:Platinum; D004561:Transcutaneous Electric Nerve Stimulation / Q000295:instrumentation / Q000379:methods*; D014630:Vagus Nerve / Q000503:physiopathology; D055536:Vagus Nerve Stimulation / Q000295:instrumentation / Q000379:methods
chemical_list: D010984:Platinum
keywords: Electrochemical impedance spectroscopy; Selective nerve stimulation; Spiral nerve cuff; Stimulating electrode; Vagus nerve