Construction of a highly sensitive immunosensor based on antibody immunoglobulin G/3-(trimethoxysilyl) propylamine/graphene oxide for antigen-specific immunoglobulin G detection

Abstract

The aim of this study is to develop an immunosensor that has the ability to detect antigen G with properties such as very low detection of limit, remarkable with no bifunctional crosslinking species and excellent activity at physiological pH values. Immunoglobulin G (IgG) is found in all body fluids. When a specific bond occurs between the anti-immunoglobulin G and the immunoglobulin G (anti-IgG), the result is activation of the reaction against viral and bacterial diseases. For detection and determination of antibody–antigen (Rabbit IgG–AntiRabbit IgG) interactions, a novel electrochemical immunosensor based on antibody immunoglobulin G/3-(trimethoxysilyl)propylamine/graphene oxide/glassy carbon (Ab/TMSPA/GO/GCE) was fabricated by using of carboxylic groups (–COOH) on graphene oxide (GO) and by exploiting 3-(trimethoxysilyl)propylamine (TMSPA) to covalently conjugate antibody molecules. For characterization of the modification process of the surface of glassy carbon electrode(GCE), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used. The change of impedance response was used for the monitoring of the interactions of antibody with different concentrations of antigen. Based on the results obtained, with increasing concentrations of antigen, the electron transfer resistance increased. The limit of detection (DL) and linear range 400 ng mL−1 and 2–1500 µg mL−1 were obtained.