Facile preparation of copper nanoparticles in environmentally friendly solvent for DNA sensor application

Copper nanoparticles (CuNPs) were synthesized by electrochemical route using deep eutectic solvent (DES) as green solvent for bioelectrochemical platform to detect pathogens. The CuNP nucleation and growth mechanism was systematically analyzed through cyclic voltammetry (CV) and chronoamperometry (CA) methods. The 3D nucleation and adsorption contribution model was used to confirm the CuNP formation onto electrode. The kinetic parameters of the nucleation frequency per active site (A (s−1)) and the active site density of copper nucleic onto the surface of electrode (N0 (cm−2)) at different temperatures were evaluated. The morphology of CuNPs was characterized by field emission scanning electron microscopy (FE-SEM) with backscattering detectors. The element composition was analyzed by energy dispersive X-ray spectroscopy (EDX). The crystalline structure was characterized by X-ray powder diffraction (XRD). The biosensing properties of CuNPs were evaluated, thereby exhibiting direct electron transfer for sensing of Mycobacterium (M) tuberculosis DNA target with sensitivity of 42.5 µA/nM cm−2 and low detection limit of 1.0 nM. In addition, biosensor showed excellent selectivity as well as acceptable reproductivity and stability. © 2022 Elsevier Ltd