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Updated: Jan 25, 2026

Electrochemical Preparation of Poly3,4-Ethylenedioxythiophene Layers on Gold Microelectrodes for Uric Acid-Sensing Applications
Published on: July 28, 2021
Scanning electrochemical microscopy imaging of poly (3,4-ethylendioxythiophene)/thionine electrodes for lactate
Susan Warren1, Grigore Munteanu1, Dhanraj Rathod1
1Centre of Applied Science for Health (CASH), TU Dublin - Tallaght Campus, Dublin 24, Ireland.
Abstract:
Herein we report the use of scanning electrochemical microscopy (SECM) together with electrochemical and spectroscopic techniques to develop and characterise a stable and uniformly reactive chemically modified platinum electrode for NADH electrocatalysis. In order to achieve this, a range of different approaches for thionine entrapment within an electropolymerised poly (3,4-ethylendioxythiophene) (PEDOT) film were evaluated using SECM imaging in the presence of NADH, demonstrating the uniformity of the reactive layer towards NADH oxidation. The effect of electrolyte type and time scale employed during PEDOT electropolymerisation was examined with respect to thionine loading and the resulting charge transport diffusion coefficient (DCT) estimated via chronoamperometry. These studies indicated a decrease in DCT as thionine loading increased within the PEDOT film, suggesting that charge transport was diffusion limited within the film. Additionally, thionine functionalised nanotubes were formed, providing a stable support for lactate dehydrogenase entrapment while lowering the rate of thionine leaching, determined via SECM imaging. This enabled lactate determination at Eapp = 0.0 V vs Ag/AgCl over the range 0.25-5 mM in the presence of 1 mM NAD+.
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