A near-infrared fluorescent probe for in situ imaging of SO 2 flux in drug-induced liver injury.

Sulfur dioxide (SO 2 ) has been widely applied as an important additive in various foods and drugs due to its antioxidant, antiseptic and bleaching properties. SO 2 in living organisms plays a key biological role as an antioxidant in a variety of life activities. However, abnormal levels of SO 2 in both food and living organisms could cause harm and even serious illness, such as diseases related to the respiratory and cardiovascular systems and cancers. Therefore, it is of great practical significance to accurately determine the level of SO 2 in food and organisms. In this work, we synthesized a novel near-infrared ratiometric fluorescent probe (NTO) using xanthene and benzopyran as the matrix for the detection of SO 2 . NTO demonstrates a rapid response (within 8 s), high selectivity, excellent sensitivity (LOD = 3.64 μM) and a long emission wavelength (800 nm), which could be applied to SO 2 monitoring in a complex environment. NTO showed a high recovery (90%-110%) of SO 2 in food samples such as beer and rock sugar. The results of HeLa cell experiments indicate that NTO has excellent fluorescence labeling ability for SO 2 in endoexogenous-sulfide metabolism. In addition, we applied it to mice with acetaminophen (APAP)-induced acute liver injury and observed changes in SO 2 during liver injury. Based on these results, we believe that this will provide a convenient visual tool for the detection of the SO 2 content in food safety and biomedicine.