Microfluidic Immunosensor Design for the quantification of Gliadin in human serum samples

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

ANALYTICAL AND BIOANALYTICAL CHEMISTRY

SPRINGER HEIDELBERG

Año: 2010 vol. 396 p. 2921 - 2927

1618-2642

Abstract In the present article, a novel microfluidic immunosensorcoupled with electrochemical detection for antigliadinIgG antibody quantification is proposed. This devicerepresents an important tool for a fast, simple, sensitive, andautomated diagnostic for celiac disease, which is carried outthrough detection of anti-gliadin IgG antibodies present inhuman serum samples. Celiac disease (CD) is an autoimmunedisease generated by gluten protein fractions called prolamins.This pathology affects about one in 250 people around theworld, produces intestinal inflammation, villous atrophy, andcrypt hyperplasia, which causes a range of symptomsincluding altered bowel habits, malnutrition and weight loss.Our immunosensor consists of a Plexiglas device coupled to agold electrode, with a central channel containing 3-aminopropyl-modified controlled pore glass (AP-CPG). Thequantification of anti-gliadin IgG antibodies was carried outusing a heterogeneous, non-competitive enzyme-linked immunosorbentassay (ELISA) in which IgG antibodies bound togliadin protein, immobilized on AP-CPG, were determined byalkaline phosphatase (AP) enzyme-labeled second antibodiesspecific to human IgG. The p-aminophenyl phosphate (p-APP) was converted to p-aminophenol (p-AP) by AP, and theelectroactive product was quantified on a gold electrode at0.250 V. The calculated detection limits for electrochemicaldetection and the ELISA procedure were 0.52 and 2.72 URmL−1, respectively, and the within- and between-assaycoefficients of variation were below 5.8%. The optimizedprocedure was applied to the determination of anti-gliadinIgG antibodies in human serum samples.