Development of a pH-strip-based sensor for the detection of ammonia in exhaled breath as a promising method for the diagnosis of Helicobacter pylori infections

The early detection and treatment of Helicobacter pylori infections can help prevent the formation of ulcers and development of gastric cancer in humans. The urea breath test (UBT) is a noninvasive test for diagnosing H. pylori. However, isotopic-labeled UBT reagents are expensive and require specialized test equipment to detect isotopic CO₂. In this study, the development of a user-friendly, cost-effective, and alternative method for diagnosing H. pylori infections by detecting NH₃ in exhaled breath is reported. A commercial disposable pH strip is modified with sodium carboxymethylcellulose to enhance its performance in gaseous environments. The modified pH strip exhibits compatibility with both acidic (HCl and CH₃COOH) and alkaline (NH₃) gases. Furthermore, the sensor monitors the production of NH₃ resulting from fish spoilage for 72 h, highlighting its real-time capabilities. The feasibility of employing this simple strip sensor to detect H. pylori infection in patients is investigated through in vitro experiments and preliminary clinical studies. The simple strip sensor is a promising alternative to the C-13 UBT for detecting H. pylori infection.