A turn-on fluorescent probe for recognition and bio-imaging in live cells and zebrafish

A new Lu 3+ selective fluorescent probe L was synthesized and characterized. The optical properties of L were investigated by using absorption and fluorescence spectral studies in 7 : 3 (v/v) aqueous dimethyl sulphoxide. Upon addition of Lu 3+ in a pH 4 (acetate buffer) solution of L , the weakly fluorescent probe L became highly fluorescent. The fluorescence intensity increased five-fold at 490 nm with excitation at 437 nm. The formation of 2 : 1 complexation between L and Lu 3+ was confirmed by Job's plot. The binding constant ( K a , 1.43 × 10 4 M −1 ) was determined by the Benesi-Hildebrand (BH) method. The limit of detection (LOD) of Lu 3+ using L was found to be 23 nM. The binding mechanism of L with Lu 3+ was studied by 1 H-NMR, ESI mass spectroscopy, and theoretical studies. Further, the probe L was successfully used to bioimage Lu 3+ in a zebrafish gill cell line (DrG) and in the yolk, papillae of the eyes, and head of zebrafish embryos ( Danio rerio ), therefore providing a powerful live imaging approach for investigating chemical signaling in complex multicellular systems. A high-performance fluorescent probe ( L ) for selective recognition of Lu 3+ is developed. The probe L selectively recognizes Lu 3+ via CHEF and it can detect Lu 3+ as low as 23 nM. The probe L applied in bioimaging of L u 3+ in zebrafish larvae.