Electrostatic self-assembly to fabricate ZnO nanoparticles/reduced graphene oxide composites for hypersensitivity detection of dopamine

This study introduces the self-assembly method to fabricate Zinc Oxide (ZnO) decorated reduced Graphene Oxide (ZnO-rGO) composites with higher sensitive for detection of dopamine (DA), one of the most common biomarkers of Parkinson's disease. The approach is reported to self-assembly Graphene Oxide (GO) and ZnO nanoparticles (NPs) modified by 3-aminopropyl triethoxysilane (APTES), forming ZnO-GO composites, then ZnO-rGO composites were obtained by electrochemical reduction of ZnO-GO composites. Utilizing differential pulse voltammetry (DPV), we found ZnO-rGO composites fabricated by the method of self-assembly reduced the agglomeration of ZnO and GO and showed a higher sensitivity for detection of DA than the dopamine electrochemical sensor previously reported. The fabricated sensor showed a linear dynamic range on 5-70 mu M with a LOD of 0.167 mu M (S/N = 3) and a sensitivity of 458nA/mu M in response to DA. Finally, the as-prepared ZnO-rGO composite displayed an excellent detection recovery of 98.8 similar to 101.2% in human serum.