An Enhanced Amperometric HER2 Immunosensor for Early Detection of Breast Cancer

Human epithelium receptor 2(HER2) is the most important breast cancer biomarker, whose increased level in blood is very important for detection of breast cancer at early stage We describe herein the enhancement of an HER2 antibody based amperometric immunosensor for detection of breast cancer, by graphene (Gr) sheets. The working electrode i.e. anti-HER2/Gr-sheets/PGE was characterized using cyclic voltammetry, scanning electron microscopy and electrochemical impedance spectra. The immunosensor had optimum activity at pH 7.0, 25°C, and antibody concentration of 18 µg/ml. It exhibited a linearity in the concentration range 1 fg/ml to 20 ng/ml, with a detection limit (LOD) of 0.85fg/ml. The immunosensor was employed to determine HER2 concentrations in sera of apparently healthy women and those women suffering from breast cancer at early stage. It was increased significantly(p<0.1) in cancer patients compared to apparently healthy persons. The sensor lost 41% of its original activity within 75 days of its regular use, when stored dry at 40 C.