A Fluorescent Probe with Large Stokes Shift Based on Benzothiadiazole Scaffolds for Selective Detection of Hg2+ in Lysosomes and Its Application in Biological Imaging

Abstract Mercury is highly toxic, and appropriate amounts of the mercury‐selenium complex can protect plasma. However, when excessive mercury (II) ions (Hg 2+ ) are exposed to human skin or ingested directly, it can lead to irreversible accumulation in the body. Therefore, detecting the presence of Hg 2+ in cells is important. A novel fluorescent probe BTD‐Hg‐Lyso was designed and constructed based on the intramolecular charge transfer mechanism. Thiotaldehyde could specifically recognize Hg 2+ so that the probe could produce a fluorescence enhancement effect. In addition, the fluorescent probe BTD‐Hg‐Lyso exhibited the advantages of large Stokes shift (210 nm) and good selectivity. More importantly, the probe BTD‐Hg‐Lyso could be used for the determination of Hg 2+ in cellular lysosomes. BTD‐Hg‐Lyso was able to image Hg 2+ in HeLa cells, zebrafish, and tobacco seedlings (rhizome and stem) successfully.