Laccase‐based amperometric biosensor enhanced by Ni/Au/PPy‐COOH multisegmental nanowires for selective dopamine detection

Abstract

AbstractOne‐dimensional Ni/Au/PPy‐COOH nanowires with multiple segments were synthesized in this study. Smooth surfaces and magnetic properties of nanowires were investigated by scanning transmission electron microscopy (SEM), Energy‐dispersive X‐ray spectroscopy (EDX), and Electron Spin Resonance (ESR) techniques. The nanowires were used to modify the screen‐printed electrode surface and as a micro‐environment for Trametes versicolor laccase. The ability of this enzyme biosensor to detect dopamine change in human biological samples was demonstrated by a wide linear range (0.01–50 μM) and a low LOD (2.265 nM). In addition, the biosensor exhibited excellent selectivity allowing the detection of dopamine in the presence of ascorbic acid, uric acid, L‐Cys, serotonin, and glucose, with high sensitivity of reduction currents obtained at −0.2 V (vs. Ag/AgCl). The proposed biosensor allowed the detection of dopamine in commercial serum and artificial urine with recovery values close to 100 %. It also demonstrated reproducibility, reusability, and long‐term storage stability. The sensitivity, Kmapp, and Imax values of the biosensor were determined as 2.05 μM and 1.03 μA, respectively. The LAC‐Ni/Au/PPy‐COOH/NAF/SPE biosensor is a reliable design for detecting dopamine with a wide linear range.