A photocycle-mediated fluorescence wavelength shifting diarylethene probe for sensing and its applications in bioimaging.

Sulfur dioxide (SO2) and its derivatives, sulfites (HSO3-/SO32-), as significant environmental pollutants and biologically active molecules, can cause severe harm to human health when present in excessive amounts. Currently, once the molecular structure of most fluorescent probes used for detecting this chemical substance is determined, they usually have fixed absorption and emission wavelengths, which limits their application in complex environments. Herein, our work breaks through this limitation by designing and synthesizing a novel photo-responsive diarylethene fluorescent probe (DC-QO). Unlike traditional probes, the fluorescence intensity and emission wavelength of DC-QO can be regulated through UV-Vis light radiation cycles, demonstrating unique multi-wavelength tunability. This characteristic stems from the structural transformation of the probe molecule under light stimulation, enabling programmable control of the fluorescence signal. Additionally, this probe also possesses aggregation-induced emission (AIE) properties, with an emission wavelength that can be red-shifted to 655 nm in aqueous environments, and achieves a detection limit for SO32- of 0.19 μM, along with excellent selectivity. Cell and zebrafish imaging experiments confirmed its good biocompatibility and practical application value. This work not only provides a new method for HSO3- detection but also opens up a new path for the development of light-response probes.