Development Of Novel Fluorescence/Phosphorescence Molecule Probes And Their Biological Applications

Fluorescence/phosphorescence analysis method has been widely used to probe metal ions, small molecules and macromolecules in biological or environmental samples, and to the real-time in-situ bio-imaging analysis of cancer cells and tissues. Synthesis of the fluorescence/phosphorescence probe molecule with high sensitivity and selectivity as well as good biocompatibility and targeting properties is a key factor for this method. From the perspective of molecular design and tailor, this paper aims to develop novel fluorescence/phosphorescence molecule probes with specific responses to some biologically active species, to establish the corresponding qualitative or quantitative analysis systems, and to explore their application feasibility in agricultural products detection, environmental monitoring and tumor diagnosis.This paper includes four chapters, and the main contents are resp ectively described as follows:The first chapter is a literature review, in which we briefly introduce the basic concepts of fluorescence and phosphorescence, the advantages of fluorescence/phosphorescence analysis method, the design principles of fluorescence/phosphorescence molecule probes, and their applications in bio-macromolecule detection, metal ion detection, intracellular metal ion recognition, microscopic fluorescence imaging and disease diagnosis.In the second chapter, Emodin and Rhein, two natural herbal active ingredients, have been used as target compounds to probe their fluorescence response to Mg2+. Two quantitative analysis systems(for Emodin: the detection range is 0~1.05×10-5 mol/L, the correlation coefficient is 0.992, and the detection limit is 3.0×10-7 mol/L(S/N = 2);for Rhein: the detection range is 0~2.1×10-5 mol/L, the correlationcoefficient is 0.998, and the detection limit is 5.52×10-7 mol/L(S/N =3).They are established by optimizing the experimental conditions such as solvent, buffer solution, pH value, and so on. The relationship between the structures of Emodin-Mg2+ and Rhein-Mg2+ complexes and their photophysical properties are also established by the Job’s method, the binding constant calculation, and the structural determination. Compared with the Emodin-Mg2+ system, the Rhein-Mg2+ system has higher selectivity, wider linear range, and stronger anti-interference ability, and the practical sample determination result by this method is consistent with that by the standard atomic absorption method, which further confirms that Rhein can be used as the fluorescence molecule probe for detection of Mg2+ in agricultural products.In the third chapter, we have developed a novel cyclometalated Pt(II)acetylide derivative bearing a bis-arylamine donor and a TPY receptor,which exhibits the H+-triggered, Zn2+-enhanced and OH--quenched phosphorescence properties following an unusual multi-channel sensing mode by switching the dπ(Pt) → π*(C^N^N) metal-to-ligand charge transfer(MLCT), the π(bis-arylamine) → π*(C^N^N) intraligand charge transfer(ICT), and the [Zn(TPY)2]2+-to-[(C^N^N)Pt(C≡C-C6H5)]intramolecular energy transfer(IET) transitions. Furthermore, with introduction of the non-selective TPY receptor into the bis-arylamine functionalized cyclometalated Pt(II) acetylide, an unexpected Zn2+-selective luminescence chemosensor has been exploited in acid solution. These results suggest its potential usage as the H+/OH--controlled ON/OFF luminescence chemosensor for zinc ion in both biological and environmental applications.In the fourth chapter, a biotinylated bipyridine-Ru(II) complex has been synthesized via a six-step chemical reaction route. Based on the well-known specific interaction between biotin and avidin(AV), aphosphorescent Ru(II) complex labeled AV protein has been obtained by using ultra filtration and freeze-drying technologies. The HABA and continuous titration experiments confirm that the ratio of the phosphorescent Ru(II) complex and AV protein is 2:1. The live cell fluorescence imaging experiment preliminary proved that the specific interaction between the phosphorescent Ru(II) complex labeled AV protein and A549 lung cancer cell is present, which lead the phosphorescent probe to selectively penetrate cell membrane and enrich in the cytoplasm. Meanwhile, its small cell toxicity and excellent resistance to photo-bleaching further suggest that the phosphorescent Ru(II) complex labeled AV protein can be likely used as a bio-imaging probe with good biocompatibility and targeting properties for cancer cells.