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

Año: 2011 vol. 409 p. 98 - 104

0003-2697

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 immunodiagnostic of Hydatidosis by an automated way. Our device consists in a plexiglas system with a central channel and a gold electrode. For the E. granulosus antigen immobilization, gold electrode was modified with the incorporation of gold nanoparticles. Immobilized antigen was allowed to react with IgG-anti-E. granulosus antibodies in samples, these were quantified by horseradish peroxidase (HRP) enzyme-labeled second 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 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 betweenassay 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.