Functionalization of niobium electrodes for the construction of impedimetric biosensors

This paper describes the development of an impedimetric immunosensor, based on niobium/niobium oxide (Nb/NbOxHy) electrodes, for the detection of atrazine. Niobium oxide was anodically formed onto niobium electrodes at 25 V in 1 M H2SO4. Hydrous oxide layers were then silanized with APTES, and using glutaraldehyde as a cross linker, Fab fragment k47 antibody was covalently immobilized onto the surface of the electrodes. Electrochemical impedance spectroscopy (EIS) was used to characterize the building-up of the immunosensors as well as the binding of atrazine to its specific antibody. In presence of ferricyanide redox species and under a cathodic polarization voltage (− 1.2 V versus SCE), the relationship between the concentration of atrazine and the change of the electron transfer resistance value was studied.