Fabrication of a sensitive electrochemical biosensor for hydrogen peroxide using the immobilized hemoglobin on a nanocomposite consist of iron-nickel alloys and multi-walled carbon nanotubes

In this study, we investigate the direct electron-transfer reactivity of immobilized hemoglobin (Hb) onto the surface of a carbon paste electrodes (CPE) modified with nanocomposite consist of iron-nickel alloys and multi-walled carbon nanotubes. Fe-Ni nanocrystals were synthesized by a simple chemical method and then by various methods such as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been characterized. The simultaneous presence of nanocrystals of nickel-iron (Fe@Ni) and multi-walled carbon nanotubes (MWCNT) in structure of modified electrode provides a unique structure for reliable and effective interaction of Hb whit surface of electrode. The immobilized Hb maintains its bioactivities and displays an excellent electrochemical behavior. The biosensor was used to catalyze the reduction of hydrogen peroxide. The electrochemical behavior of modified electrode by various techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were evaluated. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging widely from 5.0 to 250.0 µM with a detection limit of 1.43 µM.