Small Molecule Quinoxaline Fluorescent Probe for AcO Real-Time Detection in Vivo.

Fluorescent probes to detect biologically important acetate ion (AcO) are essential for regulating substance metabolism, alleviating inflammatory symptoms, reducing cancer incidence, and diagnosing early diseases. However, the relatively small charge-to-atomic radius ratio in AcO and its triangular spatial structure pose challenges in recognition and often lead to interference from other anions in detection methods. Herein, we introduce a quinoxaline fluorescent probe, o-(4-(2-(3-oxo-3,4 -dihydroqui-noxalin-2-yl)vinyl)phenyl) dimethylaminothiophene ester (QPDMT), specifically design and synthetic for the accurate detection of AcO. This probe leverages molecular nucleophilicity and electron transfer to undergo a reaction that releases the fluorophore upon cleavage of the thioformyl ether bond, exhibiting a turn-on fluorescence response at 530 nm. QPDMT exhibits an impressively low detection limit of 30 nM, a rapid response time of 20 min, a robust linear response in the 1-9 µM range and excellent fluorescence quantum yield, 0.32. Importantly, this probe demonstrates low cytotoxicity, making it an ideal candidate for endogenous AcO detection in living cells and organisms.