A double-indole structure fluorescent probe for monitoring sulfur dioxide derivatives with distinct ratiometric fluorescence signals in mammalian cells

Small-molecule fluorogenic probes based on indole scaffold

“…In 2019 Yonghong Hu et al reported a double indole-based fluorescent probe for the detection of bisulfite with a low detection limit. 50 The probe 12 was synthesized by the Knoevenagel condensation between 1H-indole-3-carbaldehyde and quaternary ammonium salt of 1,1,2-trimethyl-1H-benzo[e] indole in the presence of piperidine. The probe in DMSO-PBS (2 : 3 v/v) showed a blue-shift absorption band from 500 nm to 300 nm with the colour change from orange to colourless after the addition of bisulfite.…”

Carbazole-based near-infrared-emitting fluorescence probe for the detection of bisulfite in live animals and real food samples

“…28 For the past few years, many fluorescent probes for HSO 3 À have been developed based on specific recognition mechanisms, including the nucleophilic reaction with the CQN bond and the aldehyde group, [29][30][31] hydrogen bonding, 32,33 and 1,2-addition reaction or Michael addition with the electron-deficit CQC bond. [34][35][36] Nevertheless, most of them still have several issues, including short emission wavelengths, [37][38][39] poor sensitivity and selectivity [40][41][42] and long response time (5-20 min). [43][44][45] The above shortcomings make it difficult to achieve real-time monitoring of HSO 3 À in live animals and real food samples quickly and accurately.…”

Small-Molecule Fluorescent Probe for Detection of Sulfite

“…In contrast to probe 37, probe 38 [71] applied HSO 3 − fluorescence imaging in live mice, which was the first time used for imaging BALB/c mice to detect SO 3 2− /HSO 3 − in live mice. In 2020, the Wang'group [72] and Zhou'group [73] designed probes 39 and 40, respectively, for bisulfite detection. Probe 39 is a ratiometric fluorescent probe that eliminates background interference and has a detection limit of 80 nM.…”