Enzymatic Electrode Obtained by Immobilizing of Urease into a Nanocomposite Film Based on Conducting Polymers and Different Additives

Abstract

The nanocomposite film was obtained by electrochemical co-polymerization of the corresponding monomers in the presence of functionalized carbon nanotubes and different additives. By immobilizing urease on a modified electrode of type nanocomposite film/platinum substrate a novel amperometric biosensor for the detection of urea was prepared. The polymeric and nanocomposite films were utilized as conducting films for amperometric urea sensing after covalent immobilization of urease onto film-coated electrode. The electrochemical performance of the modified electrode was studied by cyclic voltammetry, chronoamperometry, and scanning electron microscopy. The immobilized urease on the nanocomposite film surface exhibited an excellent electrocatalytic response toward reduction urea. Amperometric response was measured as a function of urea concentration at a fixed potential, in this case the open circuit potential. The obtained sensor showed rapid response and good reversibility. The response time was less than 10 s, while the reversible time was about 5–15 s. The enzymatic nanostructured electrode exhibited high sensitivity, a wide linear range, and low detection limit for electrochemical detection of urea.