Deep eutectic solvent-assisted galvanic replacement deposition of nickel on copper foil for non-enzymatic glucose sensing.

This study presents a novel approach that combines galvanic replacement (GRP) with a deep eutectic solvent (DES) to develop a non-enzymatic electrochemical glucose sensor. To this end, nickel was deposited onto copper foil via the GRP process in a DES medium, thereby forming a Ni/Cu interface with enhanced electrocatalytic properties. The structural, morphological, and electrochemical characterization was performed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), open-circuit potential (OCP) measurements, and cyclic voltammetry (CV), providing insight into the formation mechanism and electrochemical behaviour of the resulting Ni-DES/Cu electrode. The characterization results confirmed that the porous Ni nanostructures exhibit increased electroactive surface area and improved electron-transfer kinetics. Furthermore, their synergistic interaction with the conductive copper substrate, combined with the reversible Ni(II)/Ni(III) redox couple, significantly enhances the electrocatalytic oxidation of glucose in alkaline media. Under optimized conditions, the proposed sensor showed a wide linear range of 0.8-350 μM, a sensitivity of 1148.5 μAmM-1cm-2, and a low detection limit of 0.18 μM. The analytical performance of the Ni-DES/Cu electrode was evaluated with respect to sensitivity, linear range, LOD, LOQ, repeatability, reproducibility, selectivity, and storage stability. The successful determination of glucose levels in a human serum sample, with an average recovery of 99.6 ± 0.2% (n = 3), demonstrated the practical applicability of the proposed sensor for real-sample analysis. The use of DES-assisted galvanic replacement for glucose sensing demonstrates its potential as a promising approach for future sensor design and fabrication.