The properties of immobilized urease enzyme on nanostructured zinc oxide particles were studied at various conditions. Zinc oxide thick films were deposited on Au-sheet using organic additives and urease enzyme is immobilized at various pH (6, 7 and 8). The activity of produced biosensors was evaluated at various concentrations of urea (10-6, 10-7 and 10-8 M). The result show that when pH increased from 6.0 to 8.0, the biosensor shows an optimal response at pH=7. Also, the response of biosensor in pH=6 is lower than pH=8. With the increasing of urea concentration, the response of produced biosensor is increased and this trend was the same for three pH of solution. The results show that at optimum condition (pH=7, 10-6M), for the imprinted ZnO films on Au maximum current is 18.4 mA, while the maximum current for immobilized urease on Au sheets without ZnO films is 6.06 mA.

Keywords