Integrated microfluidic magnetic immunosensor for quantification of human serum IgG antibodies to Helicobacter pylori

SIRLEY V. PEREIRA; GERMÁN ALEJANDRO MESSINA; JULIO RABA

JOURNAL OF CHROMATOGRAPHY B

ELSEVIER

Año: 2010 vol. 878 p. 253 - 257

0378-4347

In this paper, we have developed and characterized a microfluidic magnetic immunosensor coupled to agold electrode for the rapid and sensitive quantification of human serum IgG antibodies to Helicobacterpylori. This microorganism cause peptic ulcers and chronic gastritis, affecting around the 10% of theworldpopulation. The sensor was completely automated and the antibodies detection in serum samples wascarried out using a non-competitive immunoassay based on the use of purified H. pylori antigens thatare immobilized on magnetic microspheres 3-aminopropyl-modified. The magnetic microbeads wereinjected into microchannel devices and manipulated for an external removable magnet. The IgG antibodiesin human serum sample are allowed to react immunologically with the immobilized antigens, andthe bounded antibodies are quantified by alkaline 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 an electroactive product was detected on gold layer electrode at 0.250 V. The response currentobtained from the product of enzymatic reaction is directly proportional to the activity of the enzymeand, consequently, to the amount of IgG antibodies to H. pylori in serum samples. The electrochemicaldetection can be done within 1 min and total assay time was 25 min. The calculated detection limitsfor electrochemical detection and the ELISA procedure were 0.37 and 2.1UmL−1, respectively, and thewithin- and between-assay coefficients of variation were below 5%. Our results indicate the potentialusefulness of our fabricated microbiochip for the early assessment of human serum immunoglobulin G(IgG) antibodies to H. pylori.