Ultra-high sensitive, selective, non-enzymatic dopamine sensor based on electrochemically active graphene decorated Polydiphenylamine-SiO2 nanohybrid composite

In neurotransmission process, dopamine (DA) is the key molecule. Hence, the detection of dopamine plays a vital role in the primary diagnosis of diseases which is related to the irregular levels of dopamine. In this study, we proposed the electrochemically deposited Graphene Nanosheets-Polydiphenylamine-Silica (GRNS-PDPA-SiO2) modified nanohybrid electrode for an amperometric detection of dopamine. The electrochemical oxidation of DA ensures the catalytic activity of the prepared nanohybrid composites by chronoamperometry (CA) method. The nanohybrid electrode shows linear response towards DA (1-5 mu M) in the presence of phosphate buffer solution (PBS at pH 7.0) with the regression co-efficient (R-2) of 0.98. Low detection limit with superior sensitivity of dopamine was achieved as 0.1 mu M and 0.66 mu A mu M(-1)cm(-2) respectively. The structural morphology and the chemical homogeneity of the materials were confirmed by scanning electron microscope with EDX analysis. The molecular vibration and electrochemical performances were recorded through Fourier-transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The adopted GRNS-PDPA-SiO2 modified electrode resulted in excellent sensitivity, high selectivity claims its realistic applications in the highly clinical diagnostics.