Standard cochlear implants as electrochemical sensors: Intracochlear oxygen measurements in vivo.

Autor: Weltin A; Laboratory for Sensors, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany; BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany. Electronic address: weltin@imtek.de., Kieninger J; Laboratory for Sensors, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany; BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany., Urban GA; Laboratory for Sensors, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany; BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany., Buchholz S; Department of Oto-Rhino-Laryngology, Section of Experimental and Clinical Otology, Neurobiological Research Laboratory, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany., Arndt S; Department of Oto-Rhino-Laryngology, Section of Experimental and Clinical Otology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany., Rosskothen-Kuhl N; Department of Oto-Rhino-Laryngology, Section of Experimental and Clinical Otology, Neurobiological Research Laboratory, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany. Electronic address: nicole.rosskothen-kuhl@uniklinik-freiburg.de.
Jazyk: angličtina
Zdroj: Biosensors & bioelectronics [Biosens Bioelectron] 2022 Mar 01; Vol. 199, pp. 113859. Date of Electronic Publication: 2021 Dec 09.
DOI: 10.1016/j.bios.2021.113859
Abstrakt: Cochlear implants are the most successful neural prostheses worldwide and routinely restore sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Enhancing this standard implant by chemical sensor functionality opens up new possibilities, ranging from access to the biochemical microenvironment of the implanted electrode array to the long-term study of the electrode status. We developed an electrochemical method to turn the platinum stimulation microelectrodes of cochlear implants into electrochemical sensors. The electrodes showed excellent and stable chemical sensor properties, as demonstrated by in vitro characterizations with combined amperometric and active potentiometric dissolved oxygen and hydrogen peroxide measurements. Linear, stable and highly reproducible sensor responses within the relevant concentration ranges with negligible offset were shown. This approach was successfully applied in vivo in an animal model. Intracochlear oxygen dynamics in rats upon breathing pure oxygen were reproducibly and precisely measured in real-time from the perilymph. At the same time, correct implant placement and its functionality was verified by measurements of electrically evoked auditory brainstem responses with clearly distinguishable peaks. Acute measurements indicated no adverse influence of electrical stimulation on electrochemical measurements and vice versa. Our work is ground-breaking towards advanced implant functionality, future implant lifetime monitoring, and implant-life-long in situ investigation of electrode degradation in cochlear implant patients.
(Copyright © 2021 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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