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 MnO 2 nanosheets with abundant base edges offered high external surface areas for in situ grown of Au nanoparticles (MnO 2 NSs/Au NPs). MnO 2 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 H 2 O 2 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.