Microfluidic immunosensor with gold nanoparticles platform for the quantitative 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

Año: 2011 vol. 409 p. 98 - 104

0003-2697

This article describes a microfluidic immunosensor, developed for the detection of IgG antibodies specific toEchinococcus granulosus in human serum samples, which represents an alternative tool that can be used forthe immunodiagnosis of hydatidosis in an automated way. Our device consists of a Plexiglas system with acentral channel and a gold electrode. For immobilization of the E. granulosus antigen, a gold electrode wasmodified 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. HRPin the presence of hydrogen peroxide (H2O2) catalyzes the oxidation of Q to o-benzoquinone (P). The electrochemicalreduction back to Q was detected on the gold electrode (AuE) at 0.15 V. The current obtained wasproportional to the activity of the enzyme and to the concentration of antibodies of interest. The detectionlimit for electrochemical detection was 0.091 ng ml1, and the within- and between-assay coefficients of variationwere below 6.7%. The proposed system presents many benefits, the more relevant are: reduced complexityand costs that are considered as the most wanted features for the clinical-immunodiagnostic field.