Amplified electrochemical immunoassay using HRP labeled protein as an inhibitor to silver deposition in the presence of H2O2

A novel electrochemical inummosensor with amplification effect based on the enzyme inhibition of silver deposition was proposed. In this method, the capture antibody was first immobilized onto a gold electrode via a self-assembled layer. After a sandwich inummoreaction, HRP labeled antibody was bound to the gold electrode. The HRP on the electrode inhibited silver deposition when the electrode was incubated in hydroquinone-H2O2 solution and silver ion solution. The linear sweep voltammetry was chosen to detect the deposited silver and the result showed that the peak current was linearly proportional to the content of IgG in the range of 50 to 2500 ng/mL with a detection limit of 35 ng/mL.