2. Immunosensor for rapid quantification of human serum IgG antibodies to Helicobacter pylori.

GERMÁN ALEJANDRO MESSINA; PATRICIA WANDA STEGE; IRMA ESTER DE VITO; ROBERTO A. OLSINA; JULIO RABA

Merlo, San Luis. Argentina.

Congreso; Cuyo Biology Society. XXII Annual Scientific Meeting.; 2004

Helicobacter pylori is a microorganism that, in contact with the gastric epithelium cause chronic gastritis, peptic ulcers and gastric carcinoma. In this study we report an amperometric immunosensor with rotation, incorporated into a flow injection system, for rapid and sensitive quantification of human serum immunoglobulin G (IgG) antibodies to H. pylori. Antibodies in the serum sample are allowed to react immunologically with the purifed H. pylori antigens that are immobilized on a rotating disk. The bound antibodies are quantified by horseradish peroxidase (HRP) enzyme-labeled second antibodies specific to human IgG. HRP in the presence of hydrogen peroxide catalyzes the oxidation of hydroquinone to p-benzoquinone. The electrochemical reduction back to hydroquinone is detected on a glassy carbon electrode surface at -0.15 V. The electrochemical detection can be done within 1 min, and the analysis time does not exceed 30 min. The calculated detection limits for proposed method and the ELISA are 0.6 and 1.9 U ml-1 respectively. The amperometric immunosensor showed higher sensitivity and lower time consumed than the standard spectrophotometric detection ELISA method. The immunosensor developed in this study is able to operate as a fast, selective, and sensitive detection unit when it is incorporated into a flow injection system.