Biosensor-based serological assay for diagnosing Helicobacter pylori infection

Abstract

Helicobacter pylori causes the most common bacterial infection involving 50% of the global population. According to the World Health Organization H. pylori infection contributes to approximately 75% of the stomach cancer cases and 5.5% of all types of cancer. Therefore, timely diagnosis of the infection is highly desirable. Serological assays are widely performed for diagnosing H. pylori infection, the most frequently used one being ELISA. In the present study we showed that a serological assay can also be carried out using a biosensor based on Surface Plasmon Resonance (SPR). Unlike our previous studies where we used amplitude detection of the binding reactions, here we applied phase-sensitive detection. It was performed with a the channeled spectroscopic ellipsometer, which allowed fast measurement with high sensitivity. Thus, the detection limit achieved was more than two times lower than that of the amplitude detection. In terms of CFU, phase detection was sensitive even at 200 CFU, while amplitude detection was applicable at 3000 CFU.