A novel multi-functional fluorescent probe for dual-channel detection of SO and Hg and dynamic visualization of SO fluctuations in vivo upon mercury exposure.

Although there are many drugs used for the treatment of mercury poisoning, it is remains confused that pathological symptoms associated with Hg-induced oxidative stress. It is reported that SO can be generated as the anti-oxidant, and plays an important role in maintaining redox balance in cells. There has not yet been a study to precisely track the changes in SO during mercury ion poisoning. We developed a novel dual-response fluorescence probe (CY-SPH) for respective or successive determination of Hg and SO in neutral aqueous media. The nucleophilic addition of HSO toward CY-SPH caused a significant fluorescence enhancement at 455 nm while the Hg -triggered desulfurization of CY-SPH to the final phenolic product (CY-OH) elicited a markedly enhanced emission at 760 nm, allowing for two-color visualization of Hg and SO with good selectivity (detection limit: 67.2 nM for Hg and 34.7 nM for SO). Moreover, CY-OH could undergo further nucleophilic addition reaction with HSO and resulted in a decrease in emission at 760 nm and an increase in emission at 438 nm, enabling the ratiometric determination of SO with better sensitivity (detection limit, 3.50 nM). Significantly, CY-SPH can monitor the endogenous SO fluctuations upon mercury exposure by means of confocal fluorescence imaging, which may prove valuable for deciphering the relationship between SO levels and the mercury induced oxidative stress. We anticipated that this research will promote to understand the functions of SO under the oxidative stress by Hg.