Electrochemical urease immobilized cobalt oxide magnetic nanoparticles based biosensor for the detection of urea

Abstract

An electrochemical biosensor based on urease-immobilized cobalt oxide magnetic nanoparticles Co3O4 for the sensing of urea is proposed. Magnetic nanoparticles Co3O4 were directly attached through filtration method on Cu wire having a diameter of 500μm. The morphology and structure of magnetic particles was studied using scanning electron microscopy (SEM) and it was found that the diameter of magnetic nanoparticles Co3O4 ranges between 80-100nm. The X-Ray Diffraction (XRD) study showed that the prepared cobalt oxide particles were of high purity and the Raman spectroscopy described that the cobalt oxide magnetic nanoparticles are composed of clusters of covalent bonds with each other. Urease was immobilized onto magnetic nanoparticles Co3O4 by physical adsorption method. The electrochemical response of the urease / Co3O4 / Cu biosensor against a standard reference electrode (Ag / AgCl) was performed for logarithmic concentration of urea from 0.1mM to 80mM. The proposed biosensor shows maximum output response at neutral pH. The proposed biosensor has shown a linear response with sensitivity of 45 mV / decade and the stable output signal was attained at around 12s. Moreover, the proposed sensor showed high selectivity, repeatability and stability.