Ultrasensitive, online detection of endogenous H2S by a novel ratiometric fluorescent approach

Endogenous hydrogen sulfide (H 2 S) is a crucial biological signaling molecule in the mammals. Numerous H 2 S sensing methods have been developed, yet there remains an urgent need for portable, online and sensitive detection of H 2 S in complex samples. Herein, a ratiometric fluorescent optical fiber sensor was designed for ultrasensitive, online detection of H 2 S, using nanohybrids electrostatically self-assembled from silicon quantum dots and gold nanoclusters (AuNCs@SiQDs nanohybrids). The nanohybrids, acting as a ratiometric fluorescent probe, exhibited a specific response to H 2 S. The mechanism involved static quenching effect of H 2 S on AuNCs and fluorescence resonance energy transfer between SiQDs and AuNCs. The sensor showed a good linear response to H 2 S concentration of 0.01 ∼ 100 μM, with an ultralow detection limit of 4.33 nM. The sensor was also successfully employed for rapid detection of H 2 S in real serum samples, without tedious preprocessing. This approach offers a portable and efficient technique for on-line ultrasensitive measurement of H 2 S in complex biological samples, as well as the determination of H 2 S-mediated biomolecules. This method boasts high sensitivity and selectivity, strong anti-interference capability, portability, practicality, and ease of production, making it significant for disease research and emergency analysis.