Smartphone-based colorimetric detection of urease activity in dental plaque for point-of-care screening of Helicobacter pylori infection.

Helicobacter pylori (H. pylori) is a major pathogen associated with gastric ulcers and gastric cancer, infecting approximately half of the global population. Therefore, developing sensitive, rapid, and cost-effective detection methods for H. pylori is critical for public health. We developed an innovative microscale colorimetric microsensor integrated with smartphone ambient-light sensors for portable, on-site quantification of H. pylori-associated urease activity in dental plaque. This low-cost device (< $ 5 fabrication) employs 3D-printed components and a custom app to measure transmittance changes from urease-catalyzed urea hydrolysis with phenol red, achieving a robust correlation with commercial microplate reader absorbance (R = 0.9989). The system demonstrates exceptional Analytical sensitivity, with limits of detection of 9.75 U/L for urease And 1.709 × 10 CFU/mL for H. pylori, alongside high reproducibility (CV < 10%) And stability over 14 days. When applied to the on-site detection of dental plaque among volunteers, the smartphone-based colorimetric microsensor exhibited detection results that were highly aligned with H. pylori infections confirmed by the urea breath test. It outperformed commercial test strips And achieved 100% sensitivity, 95.5% specificity, And 97.1% accuracy. This miniaturized, smartphone-based platform offers a promising solution for home self-testing and demonstrates significant potential for enhancing H. pylori preliminary screening at the community level.