Synthesis And Application Of Novel Europium And Terbium Complex-Based Luminescent Probes

Compared with ordinary organic luminescent probes, the lanthanide complex-based luminescent probes have some advantages, such as high solubility and stability, large Stokes shift and long luminescence life time, which enable these complexes to be easily used for the time-resolved luminescence measurement to eliminate the interferences from auto-fluorescence and scattering lights. On the basis of results reported in previous literature, this doctoral dissertation chose (2,2’:6’,2"-terpyridine-6,6"-diyl)bis(methylenenitrilo)-tetrakis(acetic acid)(TTA) as a luminous antenna owing to the high luminescence quantum yield, stability, and water-solubility of its lanthanide complexes, and several lanthanide complex-based luminescent probes and chemosensors for specific detection of bioactive molecules have been designed and synthesized by introducing different recognizers to TTA ligand. The applicability of these probes for time-resolved luminescence bioassays were investigated.A unique ratiometric luminescent probe, AMTTA-Eu3+/Tb3+, has been designed and synthesized for highly sensitive detection of hROS (highly reactive oxygen species,·OH and HOC1). The ratio of the probe is based on the different variations of Tb3+emission at540nm and Eu3+emission at610nm. When the ratiometric probe was reacted with hROS, the dose-dependent increase of the ratio, I540/I610, displayed a double exponential correlation to the concentration of hROS. This unique luminescence response is pH-independent and does not affected by other ions and ROS/RNS, which provides a useful tool that can be used for luminescence detection of hROS with both time-resolved mode and ratiometric mode.Based on the photo-induced electron transfer (PeT), two novel lanthanide complex-based luminescent probes, ANMTTA-Eu3+and ANMTTA-Tb3+, have been designed and synthesized for the highly sensitive and selective time-resolved luminescence detection of hypochlorous acid (HOCl) in aqueous media. The luminescence of the probes increased remarkably after reaction with HOCl due to the elimination of the PeT process. The dose-dependent luminescence enhancements show good linearity to the concentration of HOCl. The luminescence responses of ANMTTA-Eu3+and ANMTTA-Tb3+to HOCl are pH-independent with excellent selectivity to other reactive oxygen/nitrogen species (ROS/RNS). In combination with a time-resolved luminescence microscope, the exogenous and endogenous HOCl in HeLa cells and RAW264.7macrophage cells were successfully monitored, respectively, which provides a new and valuable method for detection of HOCl in complicated biological samples.A new terbium complex-based luminescent probe, PAMTTA-Tb3+, has been designed and synthesized for the highly sensitive and selective detection of Zn2+ions. Compared with reported lanthanide complex-based luminescent probes for Zn2+ions, the selectivity of such "OFF-ON-OFF" time-resolved luminescent probe has been improved remarkably due to the unique probe design. The response of PAMTTA-Tb3+to Zn2+is reversible and can be used as an excellent time-resolved luminescent probe for the detection of intracellular Zn2+ions in HeLa cells.