Highly Sensitive Detection of Peptide Hormone Prolactin Using Gold Nanoparticles-Graphene Nanocomposite Modified Electrode

Abstract

A novel amperometric immunosensor for detection of prolactin has been developed using the glassy carbon electrodes modified with graphene and electrochemically deposited gold nanoparticles. The hybrid nanocomposites not only offer a appropriate microenvironment for immobilization of primary antibodies and maintain their biological activity, but also accelerate electron transfer between the immobilized proteins and electrode substrates. In the presence of prolactin, a sandwich-type immune complex was formed on the sensing interface. Finally, the streptavidin-alkaline phosphatase was bound to the biotinylated secondary antibodies, catalyzing the hydrolysis of the substrate a-naphthyl phosphate. Under optimal conditions, the immunosensor exhibited a linear response to prolactin from 100 pg mL-1 to 50 ng mL-1, with a detection limit of 38.9 pg mL-1 (S/N=3). In addition, good specificity and reproducibility were achieved for the electrochemical immunosensor, which could be used for the detection of prolactin in real samples. Thus, the proposed strategy might provide a valuable platform for detection of prolactin for clinical immunoassay in the future.