Application Of Dissolution-Enhanced Emission-Organic Small Molecular Probes In Protein Detection

Fluorescence analysis has been widely used in environmental monitoring,food safety,disease diagnosis and other fields due to its high sensitivity,simple operation and fast response.In recent years,it has become an important means for biomolecular detection in the healthcare field.As one of the indispensable substances of cells,biological tissues and organs,proteins play a key role in life activities.Deficiency or mutation of protein,which can lead to many diseases and even death.Therefore,protein detection by fluorescence analysis has attracted the attention of a large number of researchers.Among them,organic molecular fluorescent probes have become commonly used fluorescent materials in fluorescence analysis,which is due to their advantages of small molecular weight,simple synthesis,and easy modification.However,those fluorescent probes that have been reported so far still have some shortcomings.For example,some fluorescent probes contain metal ions,or need to be tested in toxic organic solvents,which are not friendly to the environment.Moreover,most of the reported probes are designed based on AIE-type molecules,which makes a single kind of probe molecule.Therefore,this thesis mainly studies the application of novel organic small molecule probes in biological protein detection.The thesis reveals the advantages of the new molecule,and provides new insights into its mechanism of action.In this thesis,we designed a small organic molecule,1,3,6,8-tetrakis（p-benzoic acid）pyrene（TBAPy）,as a fluorescent“turn on”probe for the selective detection alkaline protein protamine in water.When the protamine aqueous solution was added to the TBAPy fluorescent probe dispersion,the fluorescence intensity of the system was enhanced by about 40 times,and the fluorescence color changed from the original no fluorescence to bright green,and the detection limit was 24.14ng m L^-1.The TBAPy/protamine system could be further used as‘‘on to on’’probe to detect the heparin.When heparin was added,the fluorescence of the TBAPy/protamine system was further enhanced,and the fluorescence color changed from green to blue at the same time.The reason for this phenomenon can be explained by dissolution-enhanced emission（DEE）that the insoluble TBAPy probe was deprotonated to form anionic species and dissolved in water.Due to the electrostatic repulsion between the anionic species,the aggregation caused quenching phenomenon（ACQ）is suppressed,resulting in enhanced fluorescence.This DEE phenomenon is different from the widely reported aggregation-induced emission（AIE）.The DEE mechanism proposed here provides a new strategy for the design of novel fluorescent probes,which is expected to play an important role in biosensing,health detection and other fields.