Abstract
Nanostructured zinc oxide (Nano-ZnO) film has been electrochemically deposited onto indium-tin-oxide (ITO) coated glass plate to co-immobilized urease (Urs) and glutamate dehydrogenase (GLDH) for urea detection. The observed reflection planes corresponding to wurtzite ZnO nanoparticles (similar to 25 nm) in XRD diffraction pattern and UV-visible absorption band at 338 nm reveal the formation of Nano-ZnO. Urs-GLDH/Nano-ZnO/ITO bioelectrode shows high sensitivity for urea detection within 10-80 mg/dL and limit of detection as 13.5 mg/dL with regression coefficient as 0.994 and Michaelis-Menten constant (K-m, 6.1 mg/dL) indicating good affinity of Urs-GLDH to urea. (C) 2009 Elsevier B.V. All rights reserved.