An Acid-Activatable Fluorescent Probe for Sulfur Dioxide in Traditional Chinese Medicines and Living cells.

ABSTRACT

Excessive sulfur dioxide (SO2) disturbs physiology of lysosomes causing diseases and threatening human health. A fluorescent probe has been regarded as one of the most attractive approaches, which is compatible with living cells and possesses high sensitivity. However, most of fluorescent probes' reaction sites are activated before they reach the destination. In this work, an acid-activatable fluorescent probe PT1 was synthesized, characterized, and used for SO2 detection. The introduction of oxazolines in PT1 enables the intelligent response of probe to release the activation stie for SO2 derivatives through Michael addition upon exposure to acid. In vitro studies showed a remarkable selectivity of PT1 to SO2 derivatives than other biothiols with a limit of detection as low as 62 nM. Precise spatiotemporal identification of lysosomal SO2 fluctuations has been successfully performed by PT1. Furthermore, PT1 can be applied for monitoring SO2 derivatives in traditional Chinese medicines.