Rational Design of a Reversible Fluorescent Probe for Sensing Sulfur Dioxide/Formaldehyde in Living Cells, Zebrafish, and Living Mice

Living
systems contain a diverse array of molecules and ions undergoing
dynamic changes by a web of interacting chemical reactions. Sulfur
dioxide (SO2) and formaldehyde (FA) can be generated endogenously
in living organisms to maintain their homeostasis, but aberrant production
of these species is implicated with some critical diseases. The dynamic
interaction between SO2 and FA on the overall health and
disease of living organisms remains challenging to elucidate owing
to a dearth of methods for monitoring dynamic fluctuation of these
transient species. Herein, we present the rational design, synthesis,
and photophysical property studies of the probe (CaP),
the first reversible fluorescent probe for investigating the dynamics
changes of SO2 and FA. Importantly, the highly desirable
attributes of the robust probe CaP (such as ultrafast
response to SO2 in less than 5 s, swift restoration by
FA in less than 1 min) make it possible to reversibly monitor the
dynamic fluctuation of endogenous SO2 and FA in real-time
in living cells for the first time. Moreover, we demonstrate the utility
of this unique probe to detect the fluctuations of SO2 and
FA in living zebrafish and murine species. This work provides a powerful
chemical tool for monitoring the dynamic interaction of endogenous
SO2 and FA, which will pave an avenue for interrogating
the intersecting correlation between SO2 and FA in health
and disease states.