A novel lipid droplets‐targeting fluorescent probe based on dicyanisophorone and carbazole for Cu2+and its application

A novel fluorescent probe, LCH, based on dicyanisophorone and carbazole, was prepared for the visual detection of Cu2+. The probe LCHcould recognize Cu2+by fluorescence quenching in EtOH/H2O (1/4, v/v) solution, which could be easily identified under the 365 nm UV lamp, and the detection limit was as low as 0.785 μM. The recognition mechanism of probe LCHwith Cu2+was determined by combining 1H NMR titration, MS, and theoretical calculations. Practical application experiments showed that probe LCHcould be used to detect Cu2+in the test strip experiments. Cell imaging experiments showed that the probe LCHowned good cell permeability and could be applied to the imaging of Cu2+in HepG2 cells. In addition, fluorescence colocalization experiments showed that LCHcould target lipid droplets. These results indicate that the probe LCHwill have a good application prospect in environmental detection and clinical medicine. A novel fluorescent probe LCH based on dicyandiamide, isophorone, and carbazole is proposed for the visual detection of Cu2+by fluorescence quenching. Its recognition mechanism is that Cu2+first coordinates with nitrogen atom and oxygen atom of the probe LCH and then hydrolyzes to form compound 2, which leads to “off” fluorescence. In addition, the fluorescent probe not only exhibited good cell permeability but also could target lipid droplets, and fluorescence imaging was successfully used to detect exogenous Cu2+in cells.