Label-free electrochemical immunosensor for sensitive HER2 biomarker detection using the core-shell magnetic metal-organic frameworks

Early diagnosis of tumors in the early stages of cancer allows for successful treatment and complete recovery. Herein, a simple and novel electrochemical immunosensor for I luman Epidermal growth factor Receptor 2 (HER2) detection was constructed employing electrocatalytic activity of the magnetic framework Fe3O4@ TMU-21. The surface of the Fe3O4 nanoparticles was functionalized with methacrylic acid (MAA) to facilitate the immobilization of TMU-21. The fabrication of the immunosensor platform is based on Fe3O4 @ TMU-21, and multi-walled carbon nanotubes (MWCNT). Their electrocatalytic activity towards the reduction of hydrogen peroxide is applied to signal immunosensor. In the presence of HER2 biomarker (Ag), the amperometric current of the decline of H2O2 decreased, which could be concluded that the establishment of Ag -Ab complexes on the electrode, and consequence blocking the electron transfer of reduction of H2O2 at the electrode surface. The analytical performance results of the immunosensor indicate that a linear relationship between the logarithm of the HER2 concentrations and amperometric responses is within the range of 1.0 pg mL(-1)-100 ng mL(-1) and the detection limit was 0.3 pg mL(-1). Remarkably, the detection result of HER2 in real human serum samples by the proposed immunosensor is well in correlation with HER2 spiked to human blood serum samples, therefore applies to the recognition of HER2 biomarker in clinical monitoring of tumor marker.