Identification and Detection of Intracellular Reactive Sulfur Species Using a Reaction-Mediated Dual-Recognition Strategy.

Reactive sulfur species (RSS) are emerging as a potential key gasotransmitter in diverse physiological processes linking two signaling molecules H 2 S and SO 2 . However, the exact roles of H 2 S and SO 2 remain unclear. A major hurdle is the shortage of accurate and robust approaches for sensing of H 2 S and SO 2 in biological systems. Herein, we report a reaction-mediated dual-recognition strategy-based nanosensor, silver nanoparticles (AgNPs)-loaded MIL-101 (Fe) (ALM) hybrids, for the simultaneous detection of H 2 S and SO 2 in a living cell. Upon exposure to H 2 S, AgNPs can be oxidized to form Ag 2 S, causing a decrease of surface enhanced Raman spectroscopy (SERS) signals of p,p'-dimercaptoazobenzene. Moreover, SO 2 reacts with the amino moiety of MIL-101 to form charge-transfer complexes, resulting in an increment of fluorescent (FL) intensity. The ALM with dual-modal signals can simultaneously analyze H 2 S and SO 2 at a concentration as low as 2.8 × 10 -6 and 0.003 μM, respectively. Most importantly, the ALM sensing platform enables targeting mitochondria and detection multiple RSS simultaneously in living cells under external stimulation, as well as displays indiscernible crosstalk between SERS and FL signals, which is very beneficial for the comprehension of physiological issues related with RSS.