Inmunosensor for Rapid Quantficaion of Human Serum IgG Antibodies againt Helicobacter pylori

MESSINA GA.; STEGE PW; DE VITO IE.; OLSINA RA.; RABA J.

Merlo, San luis

Congreso; Annual Scientific Meeting of biology; 2004

Sociedad de biología de cuyo

Helieobacter pylori is a bacterium that invades the gastric epithe­lium, causing chronic gastritis, peptic ulcers and gastric cancer. In this study we report an amperometric immunosensor with rotation, incorporated into a flow injection system, for rapid and sensitive quantification of human seric immunoglobulin G (lgG) antibodies against H. pylori. Antibodies in the serum sample are allowed to react immunologically with purified H. pylori antigens immobilized on a rotating disk. The bound antibodies are quantified by horse­radish peroxidase (HRP) enzyme-labelled second antibodies spe­cific for human IgG. In the presence of hydrogen peroxide, HRP 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 performed within 1 min, and the analysis time does not exceed 30 min. Calculated detection limits for the pro­posed method and standard ELlSA method are 0.6 and 1.9 U/mL, respectively. Thus, the amperometric immunosensor showed higher sensitivity and speed than the standard spectrophotometric detec­tion ELlSA method. The immunosensor is able to operate as a fast, selective, and sensitive detection unit when it is incorporated into a flow injection system.