Rapid electrochemical detection of levodopa using polyaniline-modified screen-printed electrodes for the improved management of Parkinson's disease

Noguchi, HK, Kaur, S, Krettli, LM, Singla, P, McClements, J, Snyder, H, Crapnell, RD ORCID: https://orcid.org/0000-0002-8701-3933, Banks, CE ORCID: https://orcid.org/0000-0002-0756-9764, Novakovic, K, Kaur, I, Gruber, J, Dawson, JA and Peeters, M (2022) Rapid electrochemical detection of levodopa using polyaniline-modified screen-printed electrodes for the improved management of Parkinson's disease. Physics in Medicine, 14. p. 100052. ISSN 2352-4510

Preview

Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (6MB) | Preview

Abstract

A portable test to rapidly determine levels of levodopa, the drug used to treat Parkinson's disease, can improve clinical management of the disease. In this study, screen-printed electrodes (SPEs) were modified with polymers to facilitate the electrochemical detection of levodopa. Cyclic voltammetry was used to deposit a thin layer of polyaniline on the electrode surface. Scanning electron microscopy revealed high surface coverage, which did not impact the electrode's conductivity. Differential pulse voltammetry measurements with the polyaniline-modified electrodes enabled the measurement of levodopa at physiologically relevant concentrations with discrimination between a common interferent (ascorbic acid) and a structurally similar compound (L-tyrosine). However, the use of the polymer layer did not permit differentiation between levodopa and dopamine; the only difference in these molecules is that levodopa has an amino acid moiety whereas dopamine has a free amine group. Density functional theory calculations demonstrated that aniline formed a hydrogen bond between the amino group of the monomer and the meta-hydroxyl group, which is present in both levodopa and dopamine, with similar binding energies (−53.36 vs −50.08 kJ mol−1). Thus, the polymer-functionalised SPEs are a valuable tool to measure compounds important in Parkinson's disease, but further refinement is needed to achieve selective detection.