TY - CHAP
T1 - Effect of pH and gel electrolyte on safe charge injection and electrode degradation of platinum electrodes
AU - Niederhoffer, Thomas
AU - Vanhoestenberghe, Anne
AU - Lancashire, Henry T.
N1 - Publisher Copyright:
© 2023 IEEE.
PY - 2023
Y1 - 2023
N2 - Platinum (Pt) is a widespread electrode material choice for neural interfaces and electrochemical biosensors, due to its supposed electrochemical inertness. However, faradaic reactions can take place at Pt electrodes, including Pt oxide formation and reduction. Repeated redox cycles of Pt can lead to Pt dissolution, which may harm the tissue and significantly reduce electrode lifetime. In this study, we investigated how the electrolyte may influence Pt dissolution mechanisms during current pulsing. Two electrolyte characteristics were considered: pH and gelation. We confirmed that empirically reported tissue damage thresholds correlate with Pt oxide formation and reduction. Varying electrolyte pH occasioned a shift in recorded potentials, however, damage thresholds correlated with the same mechanisms for all pH values. The similar behaviour observed for pH values in the central range (4 ≤ pH ≤ 10) can be explained by variations of local pH at the electrode surface. Gel electrolytes behaved comparably to solutions, which was confirmed by statistical similarity tests. This study extends the knowledge about platinum electrochemistry and shows the necessity to carefully choose the stimulation protocol and the electrolyte to avoid platinum dissolution and tissue damage.
AB - Platinum (Pt) is a widespread electrode material choice for neural interfaces and electrochemical biosensors, due to its supposed electrochemical inertness. However, faradaic reactions can take place at Pt electrodes, including Pt oxide formation and reduction. Repeated redox cycles of Pt can lead to Pt dissolution, which may harm the tissue and significantly reduce electrode lifetime. In this study, we investigated how the electrolyte may influence Pt dissolution mechanisms during current pulsing. Two electrolyte characteristics were considered: pH and gelation. We confirmed that empirically reported tissue damage thresholds correlate with Pt oxide formation and reduction. Varying electrolyte pH occasioned a shift in recorded potentials, however, damage thresholds correlated with the same mechanisms for all pH values. The similar behaviour observed for pH values in the central range (4 ≤ pH ≤ 10) can be explained by variations of local pH at the electrode surface. Gel electrolytes behaved comparably to solutions, which was confirmed by statistical similarity tests. This study extends the knowledge about platinum electrochemistry and shows the necessity to carefully choose the stimulation protocol and the electrolyte to avoid platinum dissolution and tissue damage.
KW - charge injection mechanisms
KW - damage mechanisms
KW - gel electrolyte
KW - pH electrochemistry
KW - platinum dissolution
UR - http://www.scopus.com/inward/record.url?scp=85176001951&partnerID=8YFLogxK
U2 - 10.1109/BioSensors58001.2023.10280965
DO - 10.1109/BioSensors58001.2023.10280965
M3 - Conference paper
AN - SCOPUS:85176001951
T3 - 2023 IEEE BioSensors Conference, BioSensors 2023 - Proceedings
BT - 2023 IEEE BioSensors Conference, BioSensors 2023 - Proceedings
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 1st Annual IEEE BioSensors Conference, BioSensors 2023
Y2 - 30 July 2023 through 1 August 2023
ER -