Marques, Raquel C.B.Costa Rama, EstefaníaViswanathan, SubramanianNouws, HenriCosta-García, AgustínDelerue-Matos, CristinaGonzález-García, M. Begoña2019-10-072019-10-0720180925-4005http://hdl.handle.net/10400.22/14706Cancer 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 U mL−1 for CA 15-3 and 2.9 ng mL−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.engMultiplexed immunosensorElectrochemical immunosensorBreast cancer biomarkerCA 15-3HER2-ECDjournal article10.1016/j.snb.2017.08.107