Sensitive electrochemical sensor for urea determination based on F-doped SnO2 electrode modified with ZnO-Fe3O4 nanoparticles transducer: Application in biological fluids

As a unique strategy, a sensitive urea biosensor media involving dip coated ZnO and Fe3O4 nanocomposite, at the optimized instrumental deposition conditions, on the F-doped SnO2 conducting glass was designed (Fe3O4-ZnO/SnO2:F) to achieve an excellent platform for urease enzyme (Urs) immobilization (Urs/Fe3O4-ZnO/SnO2:F). The Fe3O4-ZnO nanocomposite selection principles were based on urea biosensing improvement by Urs immobilization on ZnO nanoparticles by electrostatic adsorption, while Fe3O4 selection criteria were dependent upon giving high electronic density to the biosensor surface as an electrostatic repulsion layer at the biological media for the anionic interferents. Surface morphology characterization of the nanocomposite film by field emission-scanning electron microscopy (FE-SEM) displays nanocomposite film as an operative biosensing area for Urs enzyme immobilization. Step by step monitoring of Urs/Fe3O4-ZnO/SnO2:F biosensor fabrication was done using electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Urs/Fe3O4-ZnO/SnO2:F biosensor was exploited for urea quantification by I-V assessment The I-V consequences show high sensitivity for urea detection within 5-150 mg dL(-1) and limit of detection as 5 mg dL(-1). Consequently, the proposed method presented a potential application for producing the disposable sensor with good repeatability. Additionally, fast response of fabricated sensor can usually allow real-time analysis of real samples.