Person: Torrente Rodríguez, Rebeca Magnolia
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First Name
Rebeca Magnolia
Last Name
Torrente Rodríguez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Analítica
Area
Identifiers
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Item Electrochemical immunosensor for receptor tyrosine kinase AXL using poly(pyrrolepropionic acid)-modified disposable electrodes(Sensors and Actuators B: Chemical, 2016) Serafín González-Carrato, Verónica; Torrente Rodríguez, Rebeca Magnolia; Batlle, Montserrat; García de Frutos, Pablo; Campuzano Ruiz, Susana; Yáñez-Sedeño Orive, Paloma; Pingarrón Carrazón, José ManuelA sensitive and rapid method for the determination of the clinically relevant biomarker receptor tyrosine kinase AXL in serum involving amperometric disposable immunosensors is reported. The target protein was sandwiched between a specific capture antibody covalently immobilized on screen-printed carbon electrodes modified with electropolymerized poly(pyrrolepropionic acid) and a biotinylated detector antibody labeled with a streptavidin-horseradish peroxidase conjugate. The amperometric responses were measured at −0.20 V vs the Ag pseudo-reference electrode of the SPCE upon the addition of H2O2 in the presence of hydroquinone (HQ) as mediator. This integrated immunosensing platform showed a low limit of detection (337 pg mL−1), a good selectivity against other non-target serum proteins, and provided results statistically in agreement with those obtained by using a commercial ELISA kit. These attractive features together with the simplicity and easy automation and miniaturization of the required instrumentation make the developed methodology a promising alternative in the development of devices for on-site clinical analysis.Item Comparative evaluation of the performance of electrochemical immunosensors using magnetic microparticles and nanoparticles. Application to the determination of tyrosine kinase receptor AXL(Microchimica Acta, 2017) Serafín González-Carrato, Verónica; Torrente Rodríguez, Rebeca Magnolia; Batlle, Montserrat; García de Frutos, Pablo; Campuzano Ruiz, Susana; Yáñez-Sedeño Orive, Paloma; Pingarrón Carrazón, José ManuelElectrochemical sandwich immunoassay strategies involving the use of carboxyl-functionalized magnetic microbeads (cMBs) and magnetic nanoparticles (cMNPs) have been evaluated and compared. The proteolytically cleaved soluble Tyrosine kinase receptor sAXL was used as the target analyte. Antibodies against AXL were covalently immobilized on cMBs or cMNPs. Immunobinding of AXL was detected by means of a secondary biotinylated antibody and a streptavidinhorseradish peroxidase conjugate. The electrochemical transduction was accomplished by capturing the cMBs or cMNPs bearing the immunoconjugates onto screen-printed carbon electrodes (SPCEs) by using a small magnet. The amperometric response was measured at −0.20 V (vs the silver pseudoreference electrode of the SPCE) upon the addition of H2O2 in the presence of hydroquinone as the redox mediator. The calibration plots for AXL extended up to 7.5 ng mL−1 when cMBs were used for the preparation of the immunosensor and up to 40 ng mL−1 in the case of using cMNPs. The respective slope values were 158 (cMBs) and 43 nA mL ng−1 (cMNPs), while the achieved LODs were 74 (cMBs) and 75 pg mL−1 (cMNPs). Although the immunosensors prepared with cMBs provided a shorter range of linearity, they exhibited a 3.7-times larger sensitivity than those constructed with cMNPs. The successful application of the new strategies was demonstrated for the determination of the endogenous content of sAXL in real human serum samples (a cut-off value of 71 ng mL−1 have been established for patients with risk of heart failure). The immunosensors constructed using cMBs or cMNPs can be advanta geously compared, in terms of sensitivity and fabrication time, with the only immunosensor for AXL previously reported. In addition, these new immunosensors took approximately half time than ELISA to perform the assay.