A dual mode 'turn-on' fluorescence-Raman (SERS) response probe based on a 1 H -pyrrol-3(2 H )-one scaffold for monitoring H 2 S levels in biological samples.

Discovery of the biological signaling roles of H 2 S has spurred great interest in developing reliable methods for its accurate detection and quantification. As considerable variation in its levels is seen during pathological conditions such as sepsis, real-time quantification methods have relevance in diagnosis as well. Of various approaches, reaction-based probes which respond through 'off-on' fluorescence emission remain the most studied. Since the intensity of emission is related to the analyte concentration in these measurements, the presence of built-in features which provide an opportunity for internal referencing will be advantageous. In view of this, a dual mode response system that senses H 2 S through characteristic fluorescence and Raman (SERS) signals based on a 1 H -pyrrol-3(2 H )-one scaffold was developed and is the main highlight of this report. This probe offers several advantages such as fast response (<1 min), and high selectivity and sensitivity with a detection limit of ∼7 nM. Imaging of H 2 S in HepG2 cells, making use of the SERS signal from the thiolysis product is also demonstrated.