1,8-Naphthalimide-based 'turn-on' fluorescent sensor for the detection of zinc ion in aqueous media and its applications for bioimaging

A 1,8-naphthalimide derivative (1) was intentionally designed and synthesized as a new turn-on fluorescent probe for the detection of zinc ion in aqueous media (CH3CN/HEPES, V/V = 6:4). Remarkable enhancement of up to 13-fold in fluorescence intensity with a 38 nm red-shift was achieved in the detection of zinc ion. Compound 1 was successfully applied to the fluorescence imaging of zinc ion, with a fluorescence emission color produced in the cell nucleus different from that produced in the cytoplasm, in A549, BEAS-2B, CHO, Hela, and HepG2 cells. Furthermore, cytokinesis-block micronucleus (CBMN) assay was carried out in CHO cells using 1 and zinc ion as the imaging agents, showing that the 1-Zn2+ agent is a nucleic acid selective stain, which could be applied in MN assays in different kinds of cell lines.