A graphene quantum dots based electrochemiluminescence immunosensor for carcinoembryonic antigen detection using poly(5-formylindole)/reduced graphene oxide nanocomposite

Abstract

A novel electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of carcinoembryonic antigen (CEA) was developed using signal amplification strategy based on poly(5-formylindole)/reduced graphene oxide nanocomposite (P5FIn/erGO) and Au nanoparticle (AuNP) decorated graphene quantum dots (GQDs) (GQDs@AuNP). As an effective matrix for immobilization of primary antibody (Ab1), P5FIn/erGO nanocomposite facilitated the ion transport during the redox reactions and provided larger surface areas for the immobilization of Ab1. GQDs@AuNP was used as labels to conjugate with secondary antibody (Ab2), which improved electron transfer capability with stable ECL intensity. The multiple amplification of P5FIn/erGO and GQDs@AuNP made the ECL immunosensor have a broad linear range from 0.1pgmL^-1 to 10ngmL^-1 and a low detection limit with 3.78fgmL^-1. In addition, this ECL immunosensor performed with admirable stability and good selectivity and reproducibility as well. When this immunosensor was used for the analysis of CEA in human serum, good recoveries were obtained. Thus, there will be a promising future in the early diagnosis of cancer to detect CEA.

Keywords: Carcinoembryonic antigen; Electrochemiluminescence; Graphene oxide; Graphene quantum dots; Immunosensor; Polyindole.