Fabrication of a silver nanowire-reduced graphene oxide-based electrochemical biosensor and its enhanced sensitivity in the simultaneous determination of ascorbic acid, dopamine, and uric acid

Silver nanowire/reduced graphene oxide nanocomposites (AgNW/rGO) are synthesized using a two-step process: preparation of silver nanowire/graphene oxide (AgNW/GO) and the microwave-assisted hydrothermal (MAH) method. The nanocomposites are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analyses. Ascorbic acid (AA), dopamine (DA), and uric acid (UA) are determined simultaneously on the AgNW/rGO-modified screen-printed carbon electrodes (SPCEs) by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The results reveal that AgNW/rGO-modified SPCEs exhibit well-resolved oxidation peaks with a negative shift in peak potential and enhanced peak currents in the simultaneous determination of AA, DA and UA in comparison with the pure rGO-modified SPCEs, demonstrating the superior catalytic activity of AgNW/rGO composites. AgNW/rGO-modified SPCEs show the linear response of AA, DA and UA in the concentration range of 45-1550, 40-450 and 35-300 mu M with a detection limit of 0.81, 0.26 and 0.30 mu M (S/N = 3), respectively. The covalent bonds between AgNWs and rGOs are expected to suppress the random attachment of AgNWs and facilitate the electron transfer and reactant transport by constructing a porous and continuous electrically conductive network. The excellent sensitivity of AgNW/rGO composites makes them become promising electrode materials in the field of electrochemical biosensors.