Voltammetric immunosensor for the simultaneous analysis of the breast cancer biomarkers CA 15-3 and HER2-ECD

Cancer Antigen 15-3 (CA 15-3) and the extracellular domain of the human epidermal growth factor receptor 2 (HER2-ECD) are independent breast cancer biomarkers. The combination of their profiles (presence and concentration) could provide an important contribution to diagnostics and patient follow-up. Therefore, a disposable electrochemical immunosensor for the simultaneous detection of CA 15-3 and HER2-ECD was developed in this work. The immunosensor was constructed on a customized dual screen-printed carbon electrode. The carbon working electrodes' surfaces were first modified with in situ electrodeposited gold nanoparticles and then individually coated with either a monoclonal anti-human CA 15-3 or a monoclonal anti -human HER2-ECD antibody. After incubation with the biomarkers and monoclonal biotin-labelled detection antibodies, the antigen-antibody interactions were detected by linear sweep voltammetric analysis of enzymatically (alkaline phosphatase) generated metallic silver. The immunosensor's limits of detection for the selected biomarkers were 5.0 UmL(-1) for CA 15-3 and 2.9 ngmL(-1) for HER2-ECD. These values could allow the use of the sensor in the non-invasive control of these biomarkers in breast cancer patients. (C) 2017 Elsevier B.V. All rights reserved.