Electrochemical fabrication of ZnO-polyvinyl alcohol nanostructured hybrid film for application to urea biosensor

•Utilizing electrodeposition as a simple and controllable technique for hybrid film preparation.•Fabrication of a novel disposable impedimetric urea biosensor based on ZnO–polymer hybrid film transducer.•Exploiting PVA as transducer to supply OH functional groups for covalent immobilization of Urs.•Reducing signal of negatively charged interferents at pH 7.4 by high electron density of OH groups of hybrid film.•Application of impedimetric assessment for urea biosensing due to its rapidity, sensitivity, and repeatability. A novel urea biosensor was designed based on the electrochemical deposition of zinc oxide (ZnO) in the presence of polyvinyl alcohol (PVA) on the F-doped SnO2 conducting glass (FTO) to achieve ZnO–polymer nanostructured hybrid film as an excellent platform for urease enzyme (Urs) immobilization via covalent linking to the exposed PVA hydroxyl groups through cyanuric chloride (FTO/ZnO–polymer/Urs biosensor). PVA selection criteria was based on its water solubility, affording further electrical conductivity to the ZnO–polymer hybrid film transducer, providing high electronic density to the biosensor surface by free OH groups which acts as an electrostatic repulsion layer for the anionic interferents at the biological media, and controlling the growth and crystallization of ZnO by tuning PVA content in electrodeposition bath. Surface characterization of the ZnO–polymer hybrid film by field emission-scanning electron microscopy (FE-SEM) exhibits cavities of nanoporous film for enzyme immobilization. Monitoring of biosensor fabrication was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The impedimetric results of FTO/ZnO–polymer/Urs biosensor show high sensitivity for urea detection within 5.0–125.0mgdL−1 and limit of detection as 3.0mgdL−1. The proposed method showed potential application for fabricating disposable biosensor with good repeatability.