Novel Lanthanide Luminescence Probes For Time-resolved Fluorometric Application

Lanthanide complex-based fluorescence probes have shown great utilities in the fields of highly sensitive time-resolved fluorescence analysis, clinical diagnostics and biotechnology owing to their unique fluorescence properties including long fluorescence lifetimes, large Stokes shifts and sharp emission peaks. In this doctoral dissertation, several new lanthanide complexes with functional terpyridine polyacid ligands were designed and synthesized. After the detailed fluorescence characterizations of the complexes, the application methods of the complexes for the time-resolved fluorescence detections were established.A new europium(III) complex with a borono-substituted terpyridine polyacid ligand,(4’-borono-2,2’:6’,2"-terpyridine-6,6"-diyl) bis(methylenenitrilo) tetrakis(acetate)-Eu3+(BTTA-Eu3+), was designed and synthesized as a probe for the-time-resolved luminescence detection of hydrogen peroxide (H2O2). The complex BTTA-Eu3+is highly luminescent in aqueous media, upon reaction with H2O2to form its deboronation derivative (4’-hydroxy-2,2’:6’,2"-terpyridine-6,6"-diyl) bis(methylenenitrilo) tetrakis(acetate)-Eu3+(HTTA-Eu3+), the luminescence can be remarkably weakened in neutral and basic buffers. Because the pyridine-4-boronic acid structure of BTTA allows it to be a useful reagent for the Suzuki cross-coupling reaction with bromobenzene to synthesize (4’-phenyl-2,2’:6’,2"-terpyridine-6,6"-diyl) bis(methylenenitrilo) tetrakis(acetic acid)(PTTA), the luminescence of BTTA-Eu3+can be quenched by H2O2, while that of PTTA-Eu3+is not affected by H2O2, a new time-resolved luminescence method for tracking the kinetics of the Suzuki cross-coupling reaction between BTTA-Eu3+and bromobenzene was developed by using the H2O2-BTTA-Eu3+system to monitor the PTTA formation.A new lanthanide complex mixture-based ratiometric luminescence probe,(4’-hydroxy-2,2’:6’,2"-terpyridine-6,6"-diyl) bis(methylenenitrilo) tetrakis(acetate)-Eu3+/Tb3+(HTTA-Eu3+/Tb3+), was designed and synthesized for the pH detection. The luminescence characterization results reveal that the luminescence intensity of HTTA-Eu3+is strongly dependent on the pH value in the pH range of4.8-7.5, while that of HTTA-Tb3+is pH-independent. This unique luminescence response allows the mixture of HTTA-Eu3+and HTTA-Tb3+(the HTTA-Eu3+/Tb3+mixture) to be used as a ratiometric luminescence probe for the time-resolved luminescence detection of pH with the intensity ratio of Tb3+emission at540nm to Eu3+emission at610nm, I540nm/l610nm, as a signal. For investigating the utility of the new probe for cell imaging, the HTTA-Eu3+-loaded and HTTA-Tb3+-loaded HeLa cells were prepared, and used for the luminescence imaging measurements, respectively. The results suggest that the new probe could be a useful tool for the intercellular pH detection.A new europium(Ⅲ) complex-based luminescence probe having wider pH available range,[4’-(3-methylamino-4-aminophenoxy)-2,2’:6’,2"-terpyridine-6,6"-diyl] bis(methyle-nenitrilo) tetrakis(acetate)-Eu3+(MATTA-Eu3+), was designed and synthesized for the time-resolved luminescence detection of NO. After systemic characterizations of the luminescence response of the probe to NO, the MATTA-Eu3+-loaded PCl2cells were prepared, and the glutamate-induced NO production in the cells was successfully imaged with time-resolved luminescence imaging mode.