Arginine-functionalized graphene quantum dots@palladium composite modified pencil graphite electrode for electrochemical detection of DNA-mitomycin C interaction

In the present study, modified pencil graphite electrodes were prepared by synthesizing a novel nanocomposite with palladium and arginine-functionalized graphene quantum dots (Arg@GQDs) for the electrochemical monitoring of anticancer compound mitomycin C (MC) and double-stranded DNA (dsDNA) interaction for the first time. The oxidation responses of both guanine in DNA and the MC drug were measured in the same potential scanning range, and the drug-DNA interaction was determined by the differential pulse voltammetry (DPV) method. To improve the performance of the developed system, experimental parameters such as dsDNA and MC concentration and their interaction times were optimized. The surfaces obtained after the modification were characterized using scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Ultraviolet-Visible Spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FTIR), X-ray photon spectroscopy (XPS), Thermogravimetric analysis (TGA) cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The developed nanocomposite-modified electrodes (Arg@GQD@Pd@PGEs) provided higher guanine oxidation signals than PGEs. The limit of detection (LOD) values for dsDNA immobilized on PGE and Arg@GQD@Pd@PGEs were 0.713 pg 50 μL−1 and 0.019 pg 50 μL−1, respectively. © 2025 Elsevier B.V.