Microfluidic immunosensor with gold nanoparticles platform for the determination of IgG anti- Echinococcus granulosus antibodies

SIRLEY V. PEREIRA; FRANCO A. BERTOLINO; GERMÁN A. MESSINA; JULIO RABA

ANALYTICAL BIOCHEMISTRY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2011 p. 98 - 104

0003-2697

Abstract This article describes a microfluidic immunosensor, developed for the detection of IgG antibodies specific to Echinococcus granulosus in human serum samples, which represents an alternative tool that can be used for the immunodiagnosis of hydatidosis in an automated way. Our device consists of a Plexiglas system with a central channel and a gold electrode. For immobilization of the E. granulosus antigen, a gold electrode was modified with the incorporation of gold nanoparticles. Immobilized antigen was allowed to react with IgGanti-E. granulosus antibodies in samples, and these were quantified by horseradish peroxidase (HRP) enzyme-labeled secondary antibodies specific to human IgG using catechol (Q) as enzymatic mediator. HRP in the presence of hydrogen peroxide (H2O2) catalyzes the oxidation of Q to o-benzoquinone (P). The electrochemical reduction back to Q was detected on the gold electrode (AuE) at _0.15 V. The current obtained was proportional to the activity of the enzyme and to the concentration of antibodies of interest. The detection limit for electrochemical detection was 0.091 ng ml_1, and the within- and between-assay coefficients of variation were below 6.7%. The proposed system presents many benefits, the more relevant are: reduced complexity and costs that are considered as the most wanted features for the clinical-immunodiagnostic field.