A highly selective turn-on fluorescent sensor for Cu(ii) based on an NSe2 chelating moiety and its application in living cell imaging.

In this study, a boron-dipyrromethene (BODIPY)-based fluorescent chemosensor was developed for metal ion sensing. It was found that containing an NSe2 moiety exhibited high selectivity for Cu(2+) detection while in the presence of Cu(2+) displayed significant fluorescence enhancement. However, the metal ions Ag(+), Ca(2+), Co(2+), Cr(3+), Fe(2+), Fe(3+), Hg(2+), K(+), Mg(2+), Mn(2+), Ni(2+), Pb(2+), and Zn(2+) produced only minor changes in the fluorescence values of the system. The binding constant (Ka) of Cu(2+) binding to was found to be 7.28 × 10(3) M(-1). The binding ratio of -Cu(2+) complexes was determined from the Job plot to be 1 : 1. The maximum fluorescence enhancement caused by Cu(2+) binding to was observed over the pH range 5.0-9.0. Additionally, the methyl thiazolyl tetrazolium (MTT) assay demonstrated the to have low cytotoxicity. Confocal fluorescence microscopy imaging using RAW264.7 cells showed that could be used as an effective fluorescent probe for detecting Cu(2+) in living cells.