A novel mitochondria-targetted near-infrared fluorescent probe for selective and colorimetric detection of sulfite and its application in vitro and vivo.

Overdoses of SO and its derivatives (SO/HSO) in food or organisms are harmful to health. To detect SO/HSO, a novel NIR fluorescent probe 1, based upon the intramolecular charge transfer (ICT) mechanism, was developed. This probe was easily synthesized, and gave noticeable colorimetric and linear fluorescence changes at 690 nm after reaction with sulfite from 3.13 to 200 µM. Moreover, probe 1 displayed high sensitivity (LOD = 0.46 µM), excellent selectivity (among 13 kinds of anions and 3 kinds of biothiols) and quick response (within 30 min) towards SO/HSO. The SO/HSO sensing mechanism was confirmed as the Michael addition reaction. Furthermore, the probe showed wide applications for measuring SO/HSO in real samples, including sugar, tap water, wine and traditional Chinese medicine. The probe could also be used to detect SO/HSO in mitochondria of HepG2 cells and zebrafish, which suggested potential application for monitoring SO derivatives in clinical diagnostics.