Detail publikace

Direct measurement of oxygen reduction reactions at neurostimulation electrodes

EHLICH, J. MIGLIACCIO, L. SAHALIANOV, I. NIKIĆ, M. BRODSKÝ, J. GABLECH, I. VU, X. INGEBRANDT, S. GLOWACKI, E.

Originální název

Direct measurement of oxygen reduction reactions at neurostimulation electrodes

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

angličtina

Originální abstrakt

Objective. Electric stimulation delivered by implantable electrodes is a key component of neural engineering. While factors affecting long-term stability, safety, and biocompatibility are a topic of continuous investigation, a widely-accepted principle is that charge injection should be reversible, with no net electrochemical products forming. We want to evaluate oxygen reduction reactions (ORR) occurring at different electrode materials when using established materials and stimulation protocols. Approach. As stimulation electrodes, we have tested platinum, gold, tungsten, nichrome, iridium oxide, titanium, titanium nitride, and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate). We use cyclic voltammetry and voltage-step amperometry in oxygenated versus inert conditions to establish at which potentials ORR occurs, and the magnitudes of diffusion-limited ORR currents. We also benchmark the areal capacitance of each electrode material. We use amperometric probes (Clark-type electrodes) to quantify the O-2 and H2O2 concentrations in the vicinity of the electrode surface. O-2 and H2O2 concentrations are measured while applying DC current, or various biphasic charge-balanced pulses of amplitude in the range 10-30 mu C cm(-2)/phase. To corroborate experimental measurements, we employ finite element modelling to recreate 3D gradients of O-2 and H2O2. Main results. All electrode materials support ORR and can create hypoxic conditions near the electrode surface. We find that electrode materials differ significantly in their onset potentials for ORR, and in the extent to which they produce H2O2 as a by-product. A key result is that typical charge-balanced biphasic pulse protocols do lead to irreversible ORR. Some electrodes induce severely hypoxic conditions, others additionally produce an accumulation of hydrogen peroxide into the mM range. Significance. Our findings highlight faradaic ORR as a critical consideration for neural interface devices and show that the established biphasic/charge-balanced approach does not prevent irreversible changes in O-2 concentrations. Hypoxia and H2O2 can result in different (electro)physiological consequences.

Klíčová slova

bioelectronics; neurostimulation; faradaic reactions; hypoxia; reactive oxygen species

Autoři

EHLICH, J.; MIGLIACCIO, L.; SAHALIANOV, I.; NIKIĆ, M.; BRODSKÝ, J.; GABLECH, I.; VU, X.; INGEBRANDT, S.; GLOWACKI, E.

Vydáno

1. 6. 2022

Nakladatel

IOP Publishing Ltd

Místo

BRISTOL

ISSN

1741-2552

Periodikum

Journal of Neural Engineering

Ročník

19

Číslo

3

Stát

Spojené království Velké Británie a Severního Irska

Strany od

036045

Strany do

36059

Strany počet

15

URL

https://iopscience.iop.org/article/10.1088/1741-2552/ac77c0

Plný text v Digitální knihovně

http://hdl.handle.net/11012/214125

BibTex

@article{BUT179261,
  author="Jiří {Ehlich} and Ludovico {Migliaccio} and Ihor {Sahalianov} and Marta {Nikić} and Jan {Brodský} and Imrich {Gablech} and Xuan Thang {Vu} and Sven {Ingebrandt} and Eric Daniel {Glowacki}",
  title="Direct measurement of oxygen reduction reactions at neurostimulation electrodes",
  journal="Journal of Neural Engineering",
  year="2022",
  volume="19",
  number="3",
  pages="15",
  doi="10.1088/1741-2552/ac77c0",
  issn="1741-2552",
  url="https://iopscience.iop.org/article/10.1088/1741-2552/ac77c0"
}