Functional Electrochemistry: On-Nerve Assessment of Electrode Materials for Electrochemistry and Functional Neurostimulation

• Published in: IEEE open journal of engineering in medicine and biology Vol. 5; pp. 59 - 65
• Main Authors: Miranda, Jason A., Rapeaux, Adrien, Samper, Isabelle C., Silveira, Carolina, Wille, David R., Hunsberger, Gerald E., Dopson, Wesley J., Yao, Huanfen, Karicherla, Annapurna, Chew, Daniel J.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bioelectricity; Bioelectronics; Charge injection; Charge materials; Computer applications; Context; Decision making; Electrical stimuli; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; Impedance; Implants; Iridium; Nerve fibers; nerve stimulation; Nerves; neural interface; Optical fiber testing; Performance assessment; Performance evaluation; Sciatic nerve; Standardization; Stimulation; Thresholds; Tin; Titanium nitride; Bioelectronics; neural interface; electrochemistry; nerve stimulation; electrode materials
• ISSN: 2644-1276; 2644-1276
• DOI: 10.1109/OJEMB.2024.3356818

Emerging therapies in bioelectronic medicine highlight the need for deeper understanding of electrode material performance in the context of tissue stimulation. Electrochemical properties are characterized on the benchtop, facilitating standardization across experiments. On-nerve electrochemistry differs from benchtop characterization and the relationship between electrochemical performance and nerve activation thresholds are not commonly established. This relationship is important in understanding differences between electrical stimulation requirements and electrode performance. We report functional electrochemistry as a follow-up to benchtop testing, describing a novel experimental approach for evaluating on-nerve electrochemical performance in the context of nerve activation. An ex-vivo rat sciatic nerve preparation was developed to quantify activation thresholds of fiber subtypes and electrode material charge injection limits for platinum iridium, iridium oxide, titanium nitride and PEDOT. Finally, we address experimental complexities arising in these studies, and demonstrate statistical solutions that support rigorous material performance comparisons for decision making in neural interface development.