Fast responsive fluorescence turn-on sensor for Cu2+ and its application in live cell imaging

A new effective fluorescent sensor based on rhodamine was synthesized, which was induced by Cu2+ in aqueous media to produce turn-on fluorescence. The new sensor 1 exhibited good selectivity for Cu2+ over other heavy and transition metal (HTM) ions in H2O/CH3CN(7:3, v/v). Upon addition of Cu2+, a remarkable color change from colorless to pink was easily observed by the naked eye, and the dramatic fluorescence turn-on was corroborated. Furthermore, kinetic assay indicates that sensor 1 could be used for real-time tracking of Cu2+ in cells and organisms. In addition, the turn-on fluorescent change upon the addition of Cu2+ was also applied in bioimaging.