Potentiometric Immunosensor with a Novel Immobilization Procedure Based on a Nano-Au-Modified Planar Gold Electrode

A novel immobilization procedure of antibody on nano-Au modified planar gold electrode has been proposed. A pretreated planar gold electrode was first immersed in colloid Au solution for developing a nano-Au modified electrode through electrostatic interactions, and then the electrode was immerged in 4-mercapto benzoic acid (4-MB A) solution for self-assembly through the Au-S covalent bond. Finally, antibody (goat anti-mouse IgG) was immobilized by means of covalent coupling with 1-(3-Dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (NHS). The immunosensor obtained by the novel immobilization procedure showed good characteristics of response to antigen (mouse IgG), the sensitivity of the immunosensor is higher with the detection limit of 0.2 ng/ml and a wider linear range from 1 to 40 ng/ml. Otherwise, the Cyclic-voltammetric characteristics of the novel immunosensor was observed and the optimal conditions to the immunosensor were also studied in this article.