Impedance immunosensor based on receptor protein adsorbed directly on porous gold film

In this paper, a new immunosensor has been proposed based on the receptor protein adsorbed directly on a porous gold film. The film was produced electrochemically on a glassy carbon electrode in 0.08 M hydrogen tetrachloroaurate solution containing 0.004 M lead acetate with applied potential of −0.5 V (versus Ag/AgCl) for 50 s. The assay was carried out based on a sandwich procedure. The impedance signals amplified by precipitation of an insoluble product on the electrode showed good linearity with the content of IgG in the range of 0.011-11 ng mL−1 with a detection limit of 0.009 ng mL−1. The gold film was characterized by scanning electron microscopy and the results showed porous gold nanoclusters were electrochemically deposited on the glassy carbon electrode.