Abstract
Helicobacter pylori infection has been associated with various gastrointestinal disorders, most notably with the development of gastric cancer. Therefore, it is important to develop technologies for effective, rapid, sensitive, and personalized infection detection. The present study evaluates the utility of mid-infrared (MIR) exhaled breath sensors utilizing substrate-integrated hollow waveguide (iHWG) technology for the precise determination of the isotopic ratio of (13)CO(2) vs (12)CO(2) simulating conditions relevant to the detection of the presence of Helicobacter pylori in the upper gastrointestinal tract via exhaled breath analysis. For future integration of such a sensing module, e.g., into a cell phone attachment, optimized light-gas interaction and sufficient sensitivity are essential, as the diagnosis is based on detecting the presence of (13)CO(2) 30 min after administration of (13)C-labeled urea via a gel or pill, which is metabolized by H. pylori. By optimizing the light-gas interaction volume via tailoring of the iHWG, it was demonstrated that sufficient sensitivity and accuracy are achieved for detecting small changes in the isotopic composition of exhaled CO(2). While it was demonstrated that the combination of conventional Fourier-transform infrared (FTIR) spectroscopy with iHWGs indeed confirms the utility of this noninvasive breath analysis concept, further device miniaturization utilizing quantum cascade lasers is anticipated to achieve the necessary level of integration for personalized home usage.