A lanthanide-complex-based ratiometric luminescent probe specific for peroxynitrite.

A lanthanide-complex-based ratiometric luminescence probe specific for peroxynitrite (ONOO(-)), 4'-(2,4-dimethoxyphenyl)-2,2':6',2''-terpyridine-6,6''-diyl]bis(methylenenitrilo)tetrakis(acetate)-Eu(3+)/Tb(3+) ([Eu(3+)/Tb(3+)(DTTA)]), has been designed and synthesized. Both [Eu(3+)(DTTA)] and [Tb(3+)(DTTA)] are highly water soluble with large stability constants at approximately 10(20), and strongly luminescent with luminescence quantum yields of 10.0 and 9.9%, respectively, and long luminescence lifetimes of 1.38 and 0.26 ms, respectively. It was found that the luminescence of [Tb(3+)(DTTA)] could be quenched by ONOO(-) rapidly and specifically in aqueous buffers, while that of [Eu(3+)(DTTA)] did not respond to the addition of ONOO(-). Thus, by simply mixing [Eu(3+)(DTTA)] and [Tb(3+)(DTTA)] in an aqueous buffer, a ratiometric luminescence probe specific for time-gated luminescence detection of ONOO(-) was obtained. The performance of [Tb(3+)(DTTA)] and [Eu(3+)/Tb(3+)(DTTA)] as the probes for luminescence imaging detection of ONOO(-) in living cells was investigated. The results demonstrated the efficacy and advantages of the new ratiometric luminescence probe for highly sensitive luminescence bioimaging application.