On-Site Periodontitis Diagnosis via Room-Temperature Oral Exhalation H2S Sensor Based on Yb-Doped Bi2S3 Nanoribbon

A novel Yb-doped Bi 2 S 3 H 2 S sensor was fabricated for periodontitis exhalation diagnosis, which enables room temperature detection with high response (3.31/100 ppb) and superior selectivity. Mechanism analysis combined with density functional theory calculations confirms that Yb doping-induced lattice distortion in Bi 2 S 3 enhances O 2- formation and H 2 S adsorption. The sensor quantifies H 2 S produced by Porphyromonas gingivalis to confirm the association among pathogens, H 2 S and periodontitis, and is integrated into a portable analyzer for rapid, real‑time diagnosis and severity assessment of periodontitis clinically.