Direct imaging of biological sulfur dioxide derivatives in vivo using a two-photon phosphorescent probe

Abstract

Sulfur dioxide (SO2) and its derivatives sulfite and bisulfite play important roles in biological systems. However, in vivo detection of sulfite/bisulfite remains challenging.In this study, we developed a dinuclear Ir(III) complex (Ir4) as a two-photon phosphorescent probe for sulfite and bisulfite. Ir4 selectively and rapidly responded, with high sensitivity, to sulfite/bisulfite over other bio-related ions and molecules.One-photon and two-photon microscopy images revealed that Ir4 preferentially targeted mitochondria and was capable of imaging biological sulfite/bisulfite levels in vitro and in vivo. In situ sulfite generation in C. elegans was visualized by two-photon excitation real-time imaging. Finally, Ir4 was employed to monitor sulfite distribution in rat brain and other tissues. This study is the first report of the direct visualization of SO2 derivatives in vivo. These results provide new insights into the biological importance of SO2.

Two-photon luminescent metal complexes for bioimaging and cancer phototherapy

“…[131] presented the first two-photon phosphorescent probes to detect 11C) suggested the sulfite concentration in the brain is 8.39 ± 0.80 mM. These observations demonstrate that 39d is a reliable and convenient probe for intracellular sulfite determination.…”

Use of Tissue Metabolite Analysis and Enzyme Kinetics To Discriminate between Alternate Pathways for Hydrogen Sulfide Metabolism

“…A glutathione-dependent thiosulfate sulfurtransferase (TST) is likely to mediate the subsequent transfer of the sulfane sulfur from thiosulfate to glutathione in a reaction (step 2) that produces glutathione persulfide (GSS − ) and regenerates the sulfite consumed in step 1 28 . TST activity is readily detected in Caenorhabditis elegans , HepG2 cells, and rat liver slices where mitochondrial production of sulfite from thiosulfate and glutathione is observed in a reaction that can be blocked by inactivation of TST 29, 30 . Two human genes ( TSTD1 and TST ) are known to encode enzymes (TSTD1 and rhodanese, respectivly) that exhibit TST activity, as judged by properties observed with the recombinant proteins 1, 28 .…”

The Impact of Inhaled Ambient Ultrafine Particulate Matter on Developing Brain: Potential Importance of Elemental Contaminants

“…125 Early studies indicate that subsequently, its derivatives enter the blood and dissociate to form the derivatives bisulfite and sulfite, 126 both of which have been found in hippocampal slices from rat brain. 127…”