Differential pulse voltametric detection of dopamine using polyaniline-functionalized graphene oxide/silica nanocomposite for point-of-care diagnostics

In this study, a novel composite material, GO/SiO₂@PANI, was synthesized and employed as an electrochemical sensor for the detection of dopamine in urine using differential pulse voltammetry (DPV). This work introduced a first-time combination of graphene oxide (GO) with silicon dioxide (SiO₂) and the conducting polymer polyaniline (PANI) to improve dopamine detection. The composite material was synthesized using an <i>in situ</i> polymerization process, ensuring uniform integration of GO/SiO₂ with PANI. The GO/SiO₂@PANI-modified glassy carbon electrode (GCE) demonstrated a notable electrocatalytic activity for dopamine detection using DPV and CV. The performance of the sensor was evaluated across a range of dopamine concentrations, showing a linear detection range between 2 and 12 μM with a detection limit of 1.7 μM and relative standard deviation of 2.5%. The material's performance was attributed to the combined effects of graphene's surface area, PANI's conducting properties, and the structural integrity provided by SiO₂ nanoparticles (NPs). Additionally, the sensor's robustness and high selectivity were confirmed through tests with synthetic urine samples, where dopamine concentrations were detected with high accuracy. This work provides a promising avenue for the development of low-cost and efficient dopamine sensors for clinical applications.