Construction of a novel ratiometric near-infrared fluorescent probe for SO2 derivatives and its application for biological imaging

Abstract

Sulfur dioxide (SO₂) is one of the most important reactive sulfur species widely found in living organisms. SO₂ is recognized as an important regulatory factor that can modulate the cardiovascular system, with functions such as relaxing blood vessels, lowering blood pressure and acting as an anti-oxidation. Compared to fluorescence turn-on type probes, a ratiometric fluorescent probe can avoid the background fluorescence of the probe and the interference from other environmental factors. Herein, a new ratiometric-type fluorescent probe with emission in the near infrared area was developed. Upon interaction with SO₂, the emission at 750 nm decreased and a new fluorescent peak was observed in the visible region simultaneously. The novel probe showed excellent selectivity toward SO₂ among other species. In addition, the new probe exhibited little toxicity to HeLa cells and was used for imaging SO₂ in solution and the cell environment successfully with a fluorescence change in both the green and red channels.