title: Construction and application of an amperometric xanthine biosensor based on zinc oxide nanoparticles-polypyrrole composite film.
abstract: Zinc oxide nanoparticles (ZnO-NPs) were synthesized from zinc nitrate by simple and efficient method in aqueous media at 55°C without any requirement of calcinations step. A mixture of ZnO-NPs and pyrrole was eletropolymerized on Pt electrode to form a ZnO-NPs-polypyrrole (PPy) composite film. Xanthine oxidase (XOD) was immobilized onto this nanocomposite film through physiosorption. The ZnO-NPs/polypyrrole/Pt electrode was characterized by Fourier transform infrared (FTIR), cyclic voltammetry (CV), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) before and after immobilization of XOD. The XOD/ZnO-NPs-PPy/Pt electrode as working electrode, Ag/AgCl as reference electrode and Pt wire as auxiliary electrode were connected through a potentiostat to construct a xanthine biosensor. The biosensor exhibited optimum response within 5s at pH 7.0, 35°C and linearity from 0.8 μM to 40 μM for xanthine with a detection limit 0.8 μM (S/E=3). Michaelis Menten constant (K(m)) for xanthine oxidase was 13.51 μM and I(max) 0.071 μA. The biosensor measured xanthine in fish meat and lost 40% of its initial activity after its 200 uses over 100 days, when stored at 4°C.
authors.affiliation: Department of Biochemistry, M.D. University, Rohtak-124 001 Haryana, India.
authors.forename: Rooma
authors.initials: R
authors.lastname: Devi
authors.forename: Manish
authors.initials: M
authors.lastname: Thakur
authors.forename: C S
authors.initials: CS
authors.lastname: Pundir
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D005399:Fishes; D008460:Meat / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D019820:Xanthine / Q000032:analysis*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D011108:Polymers; D011758:Pyrroles; D019820:Xanthine; C067635:polypyrrole; D015034:Zinc Oxide