Near infrared light-enhanced peroxidase-like catalytic activity of copper tannic acid nanosheets for ultrasensitive detection of volatile sulfur compounds.

Monitoring the concentration of volatile sulfur compounds (VSCs) including H2S in the oral cavity allows the assessment of severity for various periodontal disease. Rational design of dual-functional copper tannic acid nanosheets with tunable peroxidase-like catalytic activity and efficient photothermal property has enabled the development of a novel near infrared (NIR) light-enhanced colorimetric platform for the ultrasensitive detection of disease-related VSCs. The system achieves NIR light-enhanced sensing performance with a broad linear range (0.125-8.000 μM) and ultralow detection limit (0.169 μM), effectively covering pathophysiological VSC concentrations in the patients with different degrees of periodontitis. Meanwhile, smartphone-assisted colorimetric analysis permits noninvasive real-time monitoring through direct photographic quantification of salivary VSC levels. The well-developed nanoplatform demonstrates an exceptional practicality for the clinical point-of-care testing by enabling visual and in situ detection of various periodontal pathogens. The current sensing strategy can well overcome the limitations of various instrumentation, maintain admirable analytical rigor, and represent a significant advancement in the affordable oral disease screening through the synergistic integration of nanozyme-assisted catalysis and photothermal signal amplification.