Ultrasensitive and rapid detection of hydrogen sulfide by an upconversion nanosensor NaYF4:Yb3+, Tm3+@NaYF4@Ag2O

Hydrogen sulfide (H 2 S), a third gas signaling molecule, is considered to play a vital role in the development and treatment of diseases. To elucidate the intricate role of H 2 S in the organism and its participation in disease processes, there is an urgent need to visualize the dynamics of H 2 S. However, most currently available molecular probes have limitations in terms of sensitivity, specificity, and precision. In this study, the safe and biocompatible upconversion nanosensor NaYF 4 :Yb 3+ , Tm 3+ @NaYF 4 anchored with Ag 2 O was successfully fabricated for H 2 S detection with an ultralow detection limit at 0.93 ng/mL. NaYF 4 :Yb 3+ , Tm 3+ @NaYF 4 @Ag 2 S is formed through in situ sulfuration reaction, and second near-infrared (NIR-II) fluorescence can be recorded upon the presence of H 2 S under 808 nm excitation. The results demonstrate the exceptional detection linearity and high specificity for H 2 S quantification. Additionally, NaYF 4 :Yb 3+ , Tm 3+ @NaYF 4 @Ag 2 O possesses a safe nature in normal and cancer cells. This nanosensor presents a NIR fluorescence imaging strategy for highly sensitive and specific detection of H 2 S, which has promises to be a practical tool for biomedical applications.