Design And Synthesis Of Water-Soluble Polythiophene-Based Fluorescent Probes With Double Binding Sites And Their Sengsing Property

Conjugated polymers have attracted considerable attention in the bioactive substance detection and disease diagnosis due to their capabilities of stronger optical trapping and enhance fluorescence signal.The chain conformation and photophysical property of water soluble polythiophene is sensitive to external stimulation,t he analytes could induce its chain conformation from random to planar,and then form supramolecular aggregates.The conformation change would induce solution color significant change and fluorescence quenching and exhibit colorimetric and fluorescent dual stimuli responsive.So recently,water soluble polythiophene has been increasingly recognized as a promising probe for various biomolecules detection,such as proteins,peptides,nucleotides,DNA and so on.Adenosine Triphosphate?ATP?is an important substrate in life activities,it is not only a universal energy source,but also an extracellular signaling mediator and involved in many biological processes.Therefore,selective detection of ATP under physiological conditions would help us to understand its important role in life.To date,a large number of polythiophene derivative probes for ATP detection have been reported,most strateg ies introduced quaternary ammonium salt groups to the side chain of polythiophene,and because the interaction between the quaternary ammonium salt and phosphate group of ATP could induce polythiophene conformation change,and output detection signal.However,these assays are usually sensitive to ionic strength,which prevents their more practical applications in complex fluids.In order to overcome this problem and challenge,we introduced quaternary ammonium salt and dipyridylamino acid?DPA?-Zn²⁺complex into the side chain of polythiophene and form a dual recognition sites,this strategy could improve the selectivity of probe and achieve real-time monitoring ATP concentration in living cells.The main contents of this thesis are as follows:1.Design,synthesis and characterization of water-soluble polythiophene probes.Fluorescence probe?Zn L?was prepared by Fe Cl₃ oxidation polymerization.The chemical structure was characterized by NMR,FT-IR and GPC.2.Investigate the sensing properties of water soluble polythiophene probe?Zn L?.UV-Vis spectroscopy,fluorescence spectroscopy,circular dichroism spectroscopy and dynamic light scattering spectroscopy were employed to investigate sensing properties of Zn L.Job's-plot result showed that Zn L and ATP form a compound with a stoichiometric ratio of 1:1.DFT calculations and ³¹P NMR results indicated that the binding of both is through electrostatic attraction and coordination.Zn L showed high selectivity to ATP under the physiological conditions of simulated cells,and its fluorescence intensity showed a good linear relationship with the concentration of ATP in the concentrat ion range of 0-96?M.3.Application of water-soluble polythiophene probe?Zn L?in enzyme activity detection.Zn L exhibit high ATP selectivity from ADP and AMP,and adenylate kinase?ADK?and ATPase can convert ATP to ADP and AMP,and then change ATP concentration in cells,based on this process,the activity of these two enzymes were real-time monitored by UV-visible absorption spectroscopy and fluorescence spectroscopy.In addition,the probe exhibit excellent biocompatibility and cell penetrability,it could be located in lysosomes and used for cell imaging and ATP concentration detection in cells.