Electrochemical immunosensor for sensitive determination of transforming growth factor (TGF) - β1 in urine.
The first amperometric immunosensor for the quantification of TGF-β1, a cytokine proposed as a biomarker for patients having or at risk for renal disease, is described in this work. The immunosensor design involves disposable devices using carboxylic acid-functionalized magnetic microparticles supported onto screen-printed carbon electrodes and covalent immobilization of the specific antibody for TGF-β1 using Mix&Go polymer. A sandwich-type immunoassay was performed using biotin-anti-TGF and conjugation with peroxidase-labeled streptavidin (poly-HRP-Strept) polymer. Amperometric measurements were carried out at -0.20V by adding hydrogen peroxide solution onto the electrode surface in the presence of hydroquinone as the redox mediator. The calibration plot allowed a range of linearity extending between 15 and 3000pg/mL TGF-β1 which is adequate for the determination of the cytokine in plasma and urine. The limit of detection, 10pg/mL, is notably improved with respect to those obtained with ELISA kits. The usefulness of the immunosensor for the determination of low TGF-β1 concentrations in real samples was evaluated by analyzing spiked urine at different pg/mL concentration levels.
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
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Sánchez-Tirado
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
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Martínez-García
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
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A
González-Cortés
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain. Electronic address: yseo@quim.ucm.es.
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Yáñez-Sedeño
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
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Pingarrón
D055910:Antibodies, Immobilized / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods; D001710:Biotin / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D006735:Horseradish Peroxidase / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D019809:Streptavidin / Q000737:chemistry; D053773:Transforming Growth Factor beta1 / Q000652:urine*
D055910:Antibodies, Immobilized; D053773:Transforming Growth Factor beta1; D001710:Biotin; D019809:Streptavidin; D006735:Horseradish Peroxidase
Electrochemical immunosensor; Signal amplification; Transforming growth factor-β1 (TGF-β1); Urine