Sulfur dioxide (SO₂), as a signal molecule, has been proved to be involved in many physiological processes. However, its levels will be affected by all kinds of factors. Herein, we specially designed a ratiometric fluorescence probe (PS-1) for the detection of SO₂. After responding to SO₂, PS-1 showed an obvious enhancement from 1.68 to 168.3 of fluorescence emission ratios at 475 and 643 nm (I₄₇₅/I₆₄₃). Besides, we found PS-1 exhibited fast response (less 15 s) and low detection limit (17.7 nM), which means PS-1 can monitor a tiny concentration change of SO₂ in the cell in real-time. Assuredly, we found that the ratiometric fluorescence changes of PS-1 in the cells pre-incubated with nystatin were more obvious than that of no treated cells. Furthermore, PS-1 was applied for imaging in mice models. These results predictability indicate that internal increasing viscosity can induce increase of sulfur dioxide concentration. Thus, PS-1 could be used to study the relationship between biological microenvironment and sulfur dioxide concentration.

二氧化硫（SO ₂），作为信号分子，已被证明参与许多生理过程。但是，其水平将受到各种因素的影响。在这里，我们专门设计了一种用于检测SO ₂的比例荧光探针（PS-1）。在响应SO _2之后，PS-1在475和643 nm（I ₄₇₅ / I ₆₄₃）处的荧光发射率从1.68显着提高到168.3 。此外，我们发现PS-1表现出快速响应（不到15 s）和低检测限（17.7 nM），这意味着PS-1可以监测SO ₂的微小浓度变化。实时地 可以肯定的是，我们发现用制霉菌素预培养的细胞中PS-1的荧光比值变化比未处理的细胞更明显。此外，将PS-1用于小鼠模型的成像。这些结果可预测性表明内部增加的粘度可引起二氧化硫浓度的增加。因此，PS-1可用于研究生物微环境与二氧化硫浓度之间的关系。