An electrochemical sensor for dopamine on a graphene-poly(3,4-ethylenedioxythiophene):polystyrene sulphonate hybrid ink nanoplatform

Dopamine can be used as a biomarker for diseases such as Alzheimer’s, bipolar disorder, schizophrenia, mania, to mention a few, as well as addiction to tobacco. Thus, its measurement is of biomedical importance. We present an easy-to-construct, one-step, electrochemical sensor for dopamine based on drop coating of a commercial graphene/poly (3,4-ethylenedioxythiophene):polystyrene sulphonate (Gr-PEDOT:PSS) hybrid ink dispersion on a bare glassy carbon electrode surface. The conductive polymer’s structural properties and composition were explored using XRD, Raman, FTIR spectroscopy and electron microscopy. The nanocomposite exhibited a uniform size distribution and functional groups such as aromatic, thiol, and olefinic bonds improved the surface chemistry between the electrolyte/analyte and the electrode. Characterization through electrochemical impedance spectroscopy and voltammetry demonstrated that the Gr-PEDOT:PSS hybrid ink sensor significantly enhances the electron transfer kinetics at the bare electrode surface and therefore improve the electrooxidation of dopamine. The sensor achieved a detection limit of 0.19 µM within a linear concentration range of 3.13–400 µM dopamine. It also exhibited high selectivity against potential interfering agents like ascorbic acid, caffeine, and urea, with recovery percentages ranging from 105 to 109% in human serum samples.