RT Journal Article T1 Comparative evaluation of the performance of electrochemical immunosensors using magnetic microparticles and nanoparticles. Application to the determination of tyrosine kinase receptor AXL A1 Serafín González-Carrato, Verónica A1 Torrente Rodríguez, Rebeca Magnolia A1 Batlle, Montserrat A1 García de Frutos, Pablo A1 Campuzano Ruiz, Susana A1 Yáñez-Sedeño Orive, Paloma A1 Pingarrón Carrazón, José Manuel AB Electrochemical 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). Theimmunosensors 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. PB Springer Wien SN 0026-3672 YR 2017 FD 2017 LK https://hdl.handle.net/20.500.14352/95386 UL https://hdl.handle.net/20.500.14352/95386 LA eng NO Serafín V, Torrente-Rodríguez R.M., Batlle M, P. García de Frutos P, Campuzano S, P. Yáñez-Sedeño P, Pingarrón J.M. Comparative evaluation of the performance of electrochemical immunosensors using magnetic microparticles and nanoparticles. application to the determination of tyrosine kinase receptor AXL. Electrochim. Acta. 2017 Agosto 24; 184: 4251-58 NO Ministerio de Economía y Competitividad (España) NO European Commission NO Comunidad de Madrid DS Docta Complutense RD 20 ago 2024