Dexamethasone Electroanalysis at Copper Nanoparticle Modified Electrodes Formed Using a Potentiostatic Triple Pulse Sequence

Abstract

Our goal is the electrochemical evaluation of anti-inflammatory/antioxidant therapeutic agents with quantification realised via electrode modifiers which facilitate detection at the appropriate level and selectivity for operation in complex clinical matrices. The analyte dexamethasone, a glucocorticosteroid and potent anti-inflammatory agent found to play a role in the treatment of severe COVID-19 cases [1], was examined in alkaline conditions at bare and copper nanoparticle (CuNP) modified glassy carbon electrodes (GCE). A three-step template free potentiostatic pulse sequence [2] was applied for the first time, realising electrodeposition of copper nanoparticles (CuNPs). This method comprised pre-treatment (E1) to remove adsorbed Cu2+ ions from the electrode surface, a nucleation pulse (E2) to seed Cu nuclei and finally a growth pulse (E3) to allow the formation of the CuNPs from the seeded nuclei, via diffusion. Optimisation was carried whereby E2 and E3 were varied along with their corresponding pulse times, where at the optimised CuNPs, the dexamethasone reduction response increased 4.5-fold, relative to the bare GCE. References [1] P. Horby, W. S. Lim, J. R. Emberson, M. Mafham, J. L. Bell, L. Linsell, N. Staplin, C. Brightling, A. Ustianowski, E. Elmahi, B. Prudon, C. Green, T. Felton, D. Chadwick, K. Rege, C. Fegan, L. C. Chappell, S. N. Faust, T. Jaki, K. Jeffery, A. Montgomery, K. Rowan, E. Juszczak, J. K. Baillie, R. Haynes, M. J. Landray. New England Journal of Medicine, 2021, 384 (8), 693-704. [2] S. K. Guin, H.S. Sharma, S. K. Aggarwal. Electrochimica Acta, 2010, 55, 1245–1257. Figure 1