Polyaniline/MnO2 nanocomposites based stainless steel electrode modified enzymatic urease biosensor

Polyaniline/MnO2 nanocomposites in different weight percent (5%, 10% and 15%) were prepared via in-situ chemical oxidation polymerization method. As-synthesized nanocomposites were electrochemically deposited on the stainless steel electrode. These modified electrodes were immobilized with urease by microencapsulation method. During deposition of the PANI/MnO2 nanocomposite on the stainless steel surface, it undergoes surface oxidation during the initial potentiometric scan of the deposition. The adsorption of the PANI/MnO2 nanocomposite takes place on the electrode surface followed by the oxidation step of stainless steel electrode. The structure of the prepared composite has been characterized by FTIR and X-ray diffraction (XRD) techniques. Cyclic voltammetry (CV) was carried out in 0.5 M NaOH for pure PANI and PANI/MnO2 nanocomposites of 5%, 10% and 15% of MnO2 in the voltage range -200 mV to + 1100 mV at the scan rate 50mVs(-1). From the cyclic voltammetry study, it can be seen that both the cathodic and anodic currents are higher at higher urease concentration. The storage stability of the PANI/MnO2/Urease biosensor electrode has also been studied. The adsorption of the urease with PANI/MnO2 modified steel electrode exhibited good urease biosensor. (C) 2015 The Authors. Published by Elsevier Ltd.