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Description
Screen-printed carbon electrodes (SPCEs) are crucial for point-of-care diagnostics but often require surface modification to meet clinical sensitivity demands. This study presents the development of high-performance electrochemical sensors utilizing reduced graphene oxide (rGO) decorated with gold nanoparticles (AuNPs) at varying concentrations (0.5, 2, and 4 wt.%). Structural and thermal analysis (XRPD, FTIR, Raman, SEM/EDS, TGA) confirmed successful nanohybrid formation, with Raman spectroscopy revealing a G-band redshift indicative of strong electronic interaction via n-type doping. The 2 wt.% AuNP/rGO hybrid demonstrated the highest graphitic ordering and thermal stability and was selected to modify SPCEs for the electrocatalytic detection of the anticancer drug doxorubicin (DOX).
Voltammetric analysis of the engineered sensor showed a highly favorable quasi-reversible redox process, resulting in a 3.3-fold increase in anodic peak current density (18.912 A cm-2) compared to bare SPCEs. Electrokinetic investigations confirmed accelerated electron transfer kinetics, yielding a reduced Tafel slope (140 mV dec-1) and an elevated heterogeneous rate constant (k0 = 2.57 10-5 cm s-1). Ultimately, the sensor delivered a 1.45-fold increase in sensitivity (0.221 A / mol L-1) and a 20.9% improvement in the limit of detection (13.193 mol L-1) in the low concentration range (0.5 - 10.5 mol L-1). These results highlight the potential of AuNP/rGO frameworks for next-generation, high-sensitivity screen-printed sensors.
Keywords: screen-printed electrodes, electrochemical sensor, doxorubicin, reduced graphene oxide, gold nanoparticles.