Electrochemical microfluidic immunosensor based on TES-AuNPs@Fe₃O₄ and CMK-8 for IgG anti-Toxocara canis determination

Author(s)

Jofre, Claudio F. ; Regiart, Matias ; Fernandez-Baldo, Martin A. ; Bertotti, Mauro ; Raba, Julio ; Messina, German A.

• Document type: Journal article
• Source: Analytica Chimica Acta; v. 1096, p. 10-pg., 2020-02-01.

Abstract

We report a microfluidic immunosensor for the electrochemical determination of IgG antibodies anti-Toxocara canis (IgG anti-T. canis). In order to improve the selectivity and sensitivity of the sensor, core-shell gold-ferric oxide nanoparticles (AuNPs@Fe3O4), and ordered mesoporous carbon (CMK-8) in chitosan (CH) were used. IgG anti-T. canis antibodies detection was carried out using a non-competitive immunoassay, in which excretory secretory antigens from T. canis second-stage larvae (TES) were covalently immobilized on AuNPs@Fe3O4. CMK-8-CH and AuNPs@Fe3O4 were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometry, cyclic voltammetry, electrochemical impedance spectroscopy, and N-2 adsorption-desorption isotherms. Antibodies present in serum samples immunologically reacted with TES, and then were quantified by using a second antibody labeled with horseradish peroxidase (HRP-anti-IgG). HRP catalyzes the reduction from H2O2 to H2O with the subsequent oxidation of catechol (H2Q) to p-benzoquinone (Q). The enzymatic product was detected electrochemically at -100mV on a modified sputtered gold electrode. The detection limit was 0.10 ng mL(-1), and the coefficients of intra- and inter-assay variation were less than 6%, with a total assay time of 20 min. As can be seen, the electrochemical immunosensor is a useful tool for in situ IgG antibodies anti-T. canis determination. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 19/06293-6 - Investigations in biological systems by using miniaturized electrochemical sensors
• Grantee: Daniel Matias Gaston Regiart
• Support Opportunities: Scholarships in Brazil - Post-Doctoral