A near-infrared fluorescent probe for in situ imaging of SO2 flux in drug-induced liver injury

Abstract

Sulfur dioxide (SO₂) has been widely applied as an important additive in various foods and drugs due to its antioxidant, antiseptic and bleaching properties. SO₂ in living organisms plays a key biological role as an antioxidant in a variety of life activities. However, abnormal levels of SO₂ 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 SO₂ 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 SO₂. 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 SO₂ monitoring in a complex environment. NTO showed a high recovery (90%–110%) of SO₂ in food samples such as beer and rock sugar. The results of HeLa cell experiments indicate that NTO has excellent fluorescence labeling ability for SO₂ in endoexogenous-sulfide metabolism. In addition, we applied it to mice with acetaminophen (APAP)-induced acute liver injury and observed changes in SO₂ during liver injury. Based on these results, we believe that this will provide a convenient visual tool for the detection of the SO₂ content in food safety and biomedicine.