Highly sensitive and fast responsive fluorescence turn-on chemodosimeter for Cu2+ and its application in live cell imaging

A rhodamine B derivative 4 containing a highly electron-rich S atom has been synthesized as a fluorescence turn-on chemodosimeter for Cu2+. Following Cu2+-promoted ring-opening, redox and hydrolysis reactions, comparable amplifications of absorption and fluorescence signals were observed upon addition of Cu2+ this Suggests that chemodosimeter 4 effectively avoided the fluorescence quenching caused by the paramagnetic nature of Cu2+. Importantly, 4 can selectively recognize Cu2+ in aqueous media in the presence of other trace metal ions in organisms (Such as Fe3+ Fe2+, Cu+, Zn2+, Cr3+, Mn2+, Co2+, and Ni2+), abundant cellular cations (such as Na+, K+, Mg2+ and Ca2+), and the prevalent toxic metal ions in the environment (Such as Pb2+ and Cd2+) Will, high sensitivity (detection limit <= 10 ppb) and a rapid response time (<= 1 min). Moreover, by virtue of the chemodosimeter as fluorescent probe for Cu2+, confocal and two-photon microscopy experiments revealed a significant increase of intracellular Cu2+ concentration and the subcellular distribution of Cu2+. which was internalized into the living HeLa cells upon incubation in growth medium supplemented with 50 mu M CuCl2 for 20 h.