Browsing by Author "Marques, Raquel C.B."
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- Detection of Arah1 (a major peanut allergen) in food using an electrochemical gold nanoparticle-coated screen-printed immunosensorPublication . Alves, Rita C.; Pimentel, Filipa B.; Nouws, Henri P.A.; Marques, Raquel C.B.; González-García, María Begoña; Oliveira, M. Beatriz P.P.; Delerue-Matos, CristinaA gold nanoparticle-coated screen-printed carbon electrode was used as the transducer in the development of an electrochemical immunosensor for Ara h 1 (a major peanut allergen) detection in food samples. Gold nanoparticles (average diameter=32 nm) were electrochemically generated on the surface of screen-printed carbon electrodes. Two monoclonal antibodies were used in a sandwich-type immunoassay and the antibody–antigen interaction was electrochemically detected through stripping analysis of enzymatically (using alkaline phosphatase) deposited silver. The total time of the optimized immunoassay was 3 h 50 min. The developed immunosensor allowed the quantification of Ara h 1 between 12.6 and 2000 ng/ml, with a limit of detection of 3.8 ng/ml, and provided precise (RSD <8.7%) and accurate (recovery >96.6%) results. The immunosensor was successfully applied to the analysis of complex food matrices (cookies and chocolate), being able to detect Ara h 1 in samples containing 0.1% of peanut.
- Voltammetric immunosensor for the simultaneous analysis of the breast cancer biomarkers CA 15-3 and HER2-ECDPublication . Marques, Raquel C.B.; Costa Rama, Estefanía; Viswanathan, Subramanian; Nouws, Henri; Costa-García, Agustín; Delerue-Matos, Cristina; González-García, M. BegoñaCancer 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.