A Novel Thiophene-Based Fluorescent Chemosensor for the Detection of Zn(2+) and CN(−): Imaging Applications in Live Cells and Zebrafish

A novel fluorescent turn-on chemosensor DHADC ((E)-3-((4-(diethylamino)-2-hydroxybenzylidene)amino)-2,3-dihydrothiophene-2-carboxamide) has been developed and used to detect Zn(2+) and CN(−). Compound DHADC displayed a notable fluorescence increase with Zn(2+). The limit of detection (2.55 ± 0.05 μM) for zinc ion was far below the standard (76 μM) of the WHO (World Health Organization). In particular, compound DHADC could be applied to determine Zn(2+) in real samples, and to image Zn(2+) in both HeLa cells and zebrafish. Additionally, DHADC could detect CN(−) through a fluorescence enhancement with little inhibition with the existence of other types of anions. The detection processes of compound DHADC for Zn(2+) and CN(−) were demonstrated with various analytical methods like Job plots, (1)H NMR titrations, and ESI-Mass analyses.