Construction Of A New Type Of Fluorescent Probe And Its Biosensing Performance

Fluorescent probes have been favored by scientific researchers as an emerging analytical test method with high sensitivity and convenience.In order to effectively detect some important biological species,this thesis designs and synthesizes three new types of fluorescent probes and studies their biosensing properties.The specific research contents are as follows:1.In order to quickly visually detect cadaverine and putrescine produced by food spoilage,this chapter designed and synthesized a new coumarin-based fluorescent probe CMA-Cl containing aldehyde groups and chlorine atoms.The aldehyde group and chlorine atom in the fluorescent probe can respectively undergo condensation reaction and nucleophilic substitution reaction with cadaverine,inhibiting the heavy atom effect of the fluorescent probe,resulting in a significant fluorescence enhancement at 475 nm,and the color of the solution changes from yellow to yellow colorless.CMA-Cl has the advantages of good selectivity,high sensitivity,low detection limit(209 n M)and fast response speed(40 min).It can quantitatively determine cadaverine and putrescine.In addition,we prepared a test paper loaded with CMA-Cl and successfully used it to visually detect the change of cadaverine during fish spoilage.2.A fluorescent probe ERC based on phenothiazine coumarin was designed and synthesized.The sulfur atom on the phenothiazine group in the fluorescent probe is selectively oxidized to sulfoxide by hypochlorous acid,which reduces the electron pushing ability of the thioether,which causes the fluorescence emission wavelength to blue shift from 609 nm to 503 nm.In addition,ERC has extremely low cytotoxicity,good cell membrane permeability and endoplasmic reticulum targeting.The probe has the advantages of good selectivity,high sensitivity,low detection limit(440 n M)and fast response speed,and has been successfully used for imaging of exogenous and endogenous HOCl in living cells and cisplatin drugs Fluorescence imaging of changes in the concentration of HOC1 in cancer cells is processed.3.In order to distinguish between Gram-negative bacteria and Gram-positive bacteria,this chapter designed and synthesized an AIE fluorescent probe CS-Py B with long-chain alkyl,pyridinium and boronic ester structures.The fluorescent probe can form a supramolecular assembly with lipopolysaccharide through electrostatic interaction,coordination interaction and hydrophobic interaction,resulting in the fluorescent probe showing an obvious fluorescence enhanced emission peak at 572 nm.Therefore,LPS can be detected based on the fluorescence emission peak.In addition,CS-Py B has excellent photostability and realizes the visual detection of Gram-negative bacteria.The three synthetic fluorescent probes all have the advantages of good selectivity,high sensitivity,low detection limit and fast response speed,providing a simple tool for the study of its biosensing performance.