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)-Eu3+/Tb3+ ([Eu3+/Tb3+ (DTTA)]), has been designed and synthesized. Both [Eu3+(DTTA)] and [Tb3+(DTTA)] are highly water soluble with large stability constants at approximate to 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 [Tb3+(DTTA)] could be quenched by ONOO- rapidly and specifically in aqueous buffers, while that of [Eu3+(DTTA)] did not respond to the addition of ONOO-. Thus, by simply mixing [Eu3+(DTTA)] and [Tb3+(DTTA)] in an aqueous buffer, a ratiometric luminescence probe specific for time-gated luminescence detection of ONOO- was obtained. The performance of [Tb3+(DTTA).] and [Eu3+/Tb3+(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.