Ortega, Francisco GRegiart, Matias DRodriguez-Martinez, Albade-Miguel-Perez, DiegoSerrano, Maria JLorente, Jose ATortella, GonzaloRubilar, OlgaSapag, KarimBertotti, MauroFernandez-Baldo, Martin A2025-01-072025-01-072021-01-19Ortega FG, Regiart MD, Rodríguez-Martínez A, de Miguel-Pérez D, Serrano MJ, Lorente JA, et al. Sandwich-Type Electrochemical Paper-Based Immunosensor for Claudin 7 and CD81 Dual Determination on Extracellular Vesicles from Breast Cancer Patients. Anal Chem. 2021 Jan 19;93(2):1143-1153.https://hdl.handle.net/10668/28334This study is focused on identifying novel epithelial markers in circulating extracellular vesicles (EVs) through the development of a dual sandwich-type electrochemical paper-based immunosensor for Claudin 7 and CD81 determination, as well as its validation in breast cancer (BC) patients. This immunosensor allows for rapid, sensitive, and label-free detection of these two relevant BC biomarkers. Under optimum conditions, the limit of detection for Claudin 7 was 0.4 pg mL-1, with a wide linear range of 2 to 1000 pg mL-1, while for CD81, the limit of detection was 3 pg mL-1, with a wide linear range of 0.01 to 10 ng mL-1. Finally, we validated Claudin 7 and CD81 determination in EVs from 60 BC patients and 20 healthy volunteers, reporting higher diagnostic accuracy than the one observed with classical diagnostic markers. This analysis provides a low-cost, specific, versatile, and user-friendly strategy as a robust and reliable tool for early BC diagnosis.enExtracellular Vesicle-Based BiomarkersDual Sandwich Electrochemical ImmunosensorClaudin 7 QuantificationLiquid Biopsy ApproachesPoint-of-Care DiagnosticsLabel-Free Sensing TechnologyBiomarkers, TumorBiosensing TechniquesBreast NeoplasmsClaudinsElectrochemical TechniquesEnzyme-Linked Immunosorbent AssayExtracellular VesiclesFemaleHumansPaperTetraspanin 28research article33301317Restricted AccessCáncer de mamaVesículas extracelularesBiomarcadores tumoralesInmunosensoresElectroquímicaDiagnóstico precozProteínas de adhesión celularSensibilidad y especificidad10.1021/acs.analchem.0c041801520-6882