Preparation Of Biomolecule/Tb Complex-Based Fluorescent Probes And Their Bioanalysis

Lanthanide fluorescent probes were constructed by employing biomolecules with structural diversity and excellent biological compatibility as bridging ligands. The unique optical features of lanthanide ions including large Stokes shift, long emission lifetime and sharp emission allow lanthanide fluorescent probes to eliminate efficiently the non-specific fluorescence from samples, instruments and other substances. Based on the advantages of biological ligands and lanthanide ions,lanthanide fluorescent probes exhibit more extensive application prospects in the field of biological research. In this paper, severel new terbium fluorescent probes by using terbium ions as central ions and biomolecules as bridging ligands were synthesized,which were then used for highly sensitive bioanalysis. The main contents are summarized as follows:1. Terbium fluorescent probes based fluorescent assay for alkaline phosphataseIn this work, a simple and sensitive fluorescent assay of studying dephosphorylation behavior of alkaline phosphatase was developed by employing a terbium guanosine monophosphate(Tb-GMP) chelate as fluorescent probe. A strong fluorescence can be observed from Tb-GMP chelate fluorescent probe. However, the addition of alkaline phosphatase would hydrolyze the phosphate group of GMP, and leading to the competition of water molecules for the coordination sphere of Tb3+. As a fluorescent probe for ALP, Tb-GMP chelate exhibits high sensitivity up to 0.001U/L detection limit. The Tb-GMP chelate fluorescent probe not only has a simpler preparation procedure, but also possesses a long enough fluorescence lifetime and excellent biological compatibility.2. Surfactants-mediated morphologies and fluorescent properties of terbium coordination polymersSurfactants can provide more nucleation sites and higher stability of lanthanide coordination polymers(LnCPs), which helps to control the size and shape of materials.In this work, we employed an amino acid-based Ln CPs as a model.Cetyltrimethylammonium bromides, sodium dodecyl sulfate and polyvinyl pyrrolidone were selected as model cationic, anionic and neutral surfactants,respectively. Phenylalanine(Phe) as side chain and terbium ions(Tb3+) were used as organic ligands and metal nodes to prepare the LnCPs, denoted as Tb/Phe CPs. Theobtained products were characterized by X-ray diffraction(XRD), Fourier-transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM) and photoluminescence(PL). The results revealed that the presence of surfactant not only has great influence on the morphologies and sizes of Tb/Phe CPs, but also affect the fluorescent properties of Tb/Phe CPs including emission intensity and lifetime.3. Functionalized terbium coordination polymer nanoparticles for selective sensing of hydrogen peroxide in biological fluidsFunctionalized lanthanide coordination polymers could be specific in response to analytes. In this work, a direct post-modification strategy was employed to prepare functionalized lanthanide coordination polymer nanoparticles(Tb/Phe-CPBA CPNPs)with specific response ability to hydrogen peroxide(H2O2) by using phenylalanine(Phe) as bridging ligands, terbium ions(Tb3+) as metal nodes and carboxyphenylboronic acids(CPBAs) as guest ligands. Tb/Phe-CPBA CPNPs emit a strong green fluorescence due to the removal of coordinated water molecules and the sensitization effect of CPBA. Upon the addition of H2O2, however, the quenched fluorescence of Tb/Phe-CPBA CPNPs can be observed owing to an intramolecular charge transfer effect. This finding led to a method for the quantitation of H2O2 in the6 μM to 1 mM concentration range and with a detection limit at 2 μM. Because of the chemoselective H2O2-mediated oxidative deboronation, Tb/Phe-CPBA CPNPs as fluorescent sensors exhibit excellent selectivity to H2O2.