Electrochemical immunosensor based on binary nanoparticles decorated rGO-TEPA as magnetic capture and Au@PtNPs as...

Using gold and magnetic nanoparticles co-decorated reduced graphene oxide-tetraethylenepentamine (rGO-TEPA/Au-MNPs) as the magnetic platform for capturing the primary antibody (Ab₁), separation and preconcentration of immunocomplex, a novel homogeneous electrochemical immunosensor was successfully developed. The newly prepared magnetic rGO-TEPA/Au-MNPs, compared with MNPs, exhibited better stability and enhanced electrical conductivity attributed to rGO-TEPA, and showed higher biorecognition efficiency due to AuNPs. In addition, Au@PtNPs were prepared and modified with secondary antibody (Ab₂) as an efficient signal probe for signal readout. Using carcinoembryonic antigen (CEA) as a model analyte, the prepared immunosensor demonstrated satisfactory properties like high stability, good repeatability and selectivity, wide linear range (5.0 pg mL^-1~200.0 ng mL^-1) as well as low detection limit (1.42 pg mL^-1). The homogenous electrochemical immunosensor was applied to the detection of CEA in human serum and was found to exhibit good correlation with the reference method. Thus, the proposed rGO-TEPA/Au-MNPs-based homogenous immunoassay platform might open up a new way for biomarker diagnosis. Graphical Abstract.