Polydopamine modified with Ag and CuO nanoparticles electrode for glucose sensor

The major purpose of this work is to fabricate electrochemical glucose sensor by employing three electrodes of polydopamine (PDA), PDA-Ag nanoparticles (NPs) and PDA-Ag-CuO nanocomposites. Ag NPs were prepared using PDA as a reducing and stabilizing agent. The fabricated electrodes were evaluated in a phosphate buffer solution working as the electrolyte, spiked with varying concentrations of glucose ranged from 4 to 40 mM using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). It was noted that Ag NPs and CuO NPs have face centered cubic and orthorhombic structures, respectively. Morphological studies displayed cauliflower shape for PDA, nanoluster spheres for Ag NPs and nanoneedles for CuO NPs ranged from 10 to 35 nm and 30 to 70 nm, respectively. The PDA-Ag NPs nanocomposite electrode exhibited a sensitivity of 1.0 × 10 −5 A·mM −1 , a correlation coefficient (R 2 ) of 96.5%, a limit of detection (LOD) of 1.73 mM, and a limit of quantification (LOQ) of 5.77 mM. It also demonstrated a relative standard deviation (RSD) of less than 1.5% and a repeatability of 1.6 × 10 −5 .PDA-Ag-CuO nanocomposite electrode achieved a sensitivity of 9.0 × 10 −6 A·mM −1 , with a strong linearity (R 2 = 99.2%), a calculated detection limit (LOD) of 1.08 mM, and a quantification limit (LOQ) of 3.60 mM. The relative standard deviation (RSD) was calculated to be below 3%, with a repeatability value of 2.8 × 10 −5 . The interference with glucose by ascorbic acid, urea, cholic acid, and dopamine was assessed, and the results indicated that PDA-Ag NPs-CuO nanocomposite electrode has a high selectivity to glucose.