A fluorescein-carbazole-based fluorescent probe for imaging of endogenous hypochlorite in living cells and zebrafish

In this article, a fluorescent probe FCZ with fluorescein-carbazole as the basic skeleton was designed and synthesized. In contrast to the presences of other coexisting anions, active oxygen and organic thiols, the probe could be turn-on, exhibiting specific fluorescence performance towards hypochlorite (CIO-). Comprehensive analyses by electrospray ionization mass spectrometry (ESI-MS), thin-layer chromatography (TLC), nuclear magnetic resonance (NMR), and density functional theory/time-dependent density functional theory (DFT/TDDFT) revealed that CIO- could react with the imine bond of the probe, forming fluorescein, resulting in a significant increase of fluorescence emission intensity. The probe has a detection limit for CIO- in water of 0.056 mu mol/L. In addition, the probe was successfully applied to detect CIO- in water samples, as well as in the imaging of CIO- in RAW264.7 cells and zebrafish. (C) 2019 Elsevier B.V. All rights reserved.