Impedimetric tumor necrosis factor-α sensor based on a reduced graphene oxide nanoparticle-modified electrode array

A surface was prepared by simple electrodeposition of reduced graphene oxide (RGO) coated with gold nanoparticles (AuNP) on an indium tin oxide microelectrode array, and its ability and applicability in a tumor necrosis factor-alpha (TNF-α) detection sensor was evaluated by electrochemical impedance spectroscopy (EIS). The AuNP-RGO hybrid structure showed improved electrical conductivity when compared with the conductivities of its individual elements and demonstrated an excellent capturing ability for TNF-α antibody-antigen binding. A quantitative determination of the TNF-α detection performance was achieved by measuring the resistance changes with varying TNF-α concentrations while using a [Fe(CN)₆]^3-/4- redox probe in EIS. The antibody covered electrode resistance increases approximately linearly (r = 0.969) with increasing antigen concentration. The proposed TNF-α sensor has a 0.43 pg mL^-1 minimum detection limit and a linear range of 1-1000 pg mL^-1.