Functional covalent organic framework H2S sensors for periodontitis monitoring and antibacterial treatment

Periodontitis is a chronic disease that can lead to irreversible tooth loss and decreased quality of life, highlighting the importance of timely monitoring. Meanwhile, hydrogen sulfide (H2S) in saliva, produced by periodontal pathogens, is a significant biomarker for monitoring periodontitis. However, the simple and portable operation required to achieve high sensitivity remains a technical challenge for directly sensing exhaled breath. In this study, by integrating the fluorescent indicator (sodium 1-pyrenebutyrate, PB) into a covalent organic framework (COF, EB-TFP), an indicator displacement assay (IDA)-based fluorescence enhanced gas sensor (EB-TFP@PB) was constructed. With the selective binding of H2S to EB-TFP, the sensor substantiated excellent sensitivity, with a limit of detection (LOD) of 1.44 ppb for H2S gas. In addition, EB-TFP@PB showed selective antibacterial activity against Staphylococcus aureus (S. aureus) under non-illuminated conditions. The antibacterial mechanism of EB-TFP@PB was further investigated using electron microscopy-related techniques. This work not only offers a reliable and sensitive design for noninvasive medical diagnosis of H2S detection based on the IDA strategy but also provides a new idea for developing highly selective antibacterial COF composite materials.