Sánchez Tirado, EstherGonzález Cortés, AraceliYáñez-Sedeño Orive, PalomaPingarrón Carrazón, José Manuel2024-12-162024-12-162020-01-17Sánchez-Tirado, E.; González-Cortés, A.; Yáñez-Sedeño, P.; Pingarrón, J. M. Electrochemical immunosensor for the determination of the cytokine interferon gamma (IFN-γ) in saliva. Talanta 2020, 211, 120761 DOI:10.1016/j.talanta.2020.1207610039-914010.1016/j.talanta.2020.120761https://hdl.handle.net/20.500.14352/112703A simple, fast and sensitive amperometric immunosensing method for the determination of the clinically relevant cytokine interferon gamma (IFN-γ) in saliva complying the requirements demanded for this kind of sample is reported. The target analyte was sandwiched between a specific capture antibody covalently immobilized on a screen-printed electrode functionalized by the diazonium salt grafting of p-aminobenzoic acid, and a biotinylated detector antibody labeled with a streptavidin-horseradish peroxidase conjugate. The amperometric responses measured at - 0.20 V vs Ag pseudo-reference electrode upon addition of hydrogen peroxide in the presence of hydroquinone as the redox mediator allowed a calibration plot with a linear range between 2.5 and 2000 pg mL−1 and a low limit of detection (1.6 pg mL−1) to be obtained. In addition, a good selectivity against other non-target proteins was achieved. The developed method was validated by analyzing a WHO 1st International Standard for IFN-γ. In addition, the immunosensor was used for the determination of the endogenous IFN-γ in saliva with results in excellent agreement with those obtained by a commercial ELISA kit.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal articlehttps://doi.org/10.1016/j.talanta.2020.120761https://www.sciencedirect.com/science/article/pii/S0039914020300527embargoed access54Interferon gamma,Electrochemical immunosensor,Aryl diazonium salt,Grafting,SalivaIFN-γ,Ciencias23 Química