Dual-Mode Electrochemical Immunosensor Based on Au@Ag NRs as Double Signal Indicator for Sensitive Detection of HER2

Abstract

Human Epidermal growth factor Receptor 2 (HER2) as the biomarker of breast cancer is desirable to achieve accurate clinical detection. In the study, the dual-mode electrochemical immunosensor was fabricated to detect HER2 with mutual authentication. The MnO2 nanosheets with abundant base edges offered high external surface areas for in situ grown of Au nanoparticles (MnO2 NSs/Au NPs). MnO2 NSs/Au NPs as the substrate materials could immobilize primary antibody and accelerate the interface electron transfer. The core–shell Au@Ag nanorods (Au@Ag NRs) were used to dual signal indicator of the immunosensor. The Au@Ag NRs could catalyze the H2O2 reduction and amplify current signal through chronoamperometry (CA). Meantime, Au@Ag NRs performed strong oxidation current signals for electron transfer between Ag and Ag+ via differential pulse voltammetry (DPV). Due to multifunction of Au@Ag NRs, high sensitivity and accuracy detection of HER2 was achieved by means of DPV and CA. Further, the immunosensor displayed wide linear range from 50 fg ml−1 to 100 ng ml−1 and 100 fg ml−1 to 100 ng ml−1, with low detection limit of 16.7 and 33.3 fg ml−1 through DPV and CA, respectively. The satisfactory detection result was obtained in human serum, indicating the dual-mode immunosensor had potential to improve efficiency and precision for clinical detection.