▎ 摘　　要

The fabrication, characterization, and application of a nanostructured zinc oxide/graphene (ZnO/Gr) transducer were described for the determination of urea concentration. For this purpose, thin films of sol-gel-synthesized ZnO nanostructure and Gr were prepared using the spin coating technique on the conductive fluorinated-tin oxide (FTO) substrate. Appropriate correlations between the spinning parameters and thin film features were established so that an efficient ZnO-Gr thin film was obtained. Field emission scanning electron microscopy (FE-SEM) images prove thin film pores to be an operative biosensing zone for urease (Urs) enzyme immobilization. Step-by-step monitoring of FTO/ZnO-Gr/Urs biosensor fabrication was achieved using electrochemical methods. The impedimetric results of a fabricated FTO/ZnO-Gr/Urs biosensor show high sensitivity for urea detection within 5.0-125.0 mg/dL and a limit of detection of 3.36 mg/dL.