A novel dual-site fluorescent probe for the one-step detection of Cys and SO in living cells.

BACKGROUND

Cysteine (Cys) is the major intracellular thiol and plays a key role in human pathology. Furthermore, endogenous sulfur dioxide (SO) is produced in mammals. Abnormal levels of SO are commonly associated with a variety of respiratory, cardiovascular, and neurological diseases. Therefore, given their important role in life activities, it is significant to construct a fluorescent probe that can detection between Cys and SO.

RESULTS

We have designed and synthesized a two-site fluorescent probe CUM with coumarin derivative and benzaldehyde molecules, which can detect and differentiate between Cys and SO through dual excitation wavelengths. Its carbon-carbon double bond reacts with Cys and undergoes a nucleophilic reaction, emitting green fluorescence at 520 nm, while SO reacts with benzaldehyde molecules in the probe CUM and undergoes a blue fluorescence at 460 nm. SO reacts with the benzaldehyde molecule of probe CUM and fluoresces blue at 460 nm. Thus, the probe CUM with two reaction sites can distinguish between Cys and SO and shows good selectivity and fast reaction speed. In addition, we successfully utilized probe CUM to image Cys and SO in human breast cancer cells (MDA-MB-231).

SIGNIFICANCE

This work provides an effective method for the molecular design of coumarin-based fluorescent probes. Probe CUM as a promising and reliable tool for the meticulous discrimination and quantification of Cys and SO in diverse biological matrices, thereby opening up new avenues for various biological systems.