Synthesis,Assembly And Bioimaging Of GFP Chromophore Derivatives

Because of its unique structure and outstanding fluorescent properties,green fluorescence protein（GFP）has been used widely as fluorescence probe in the field of biomedicine.However,compared to biosynthetic GFP,the fluorescent intensity of synthetic derivatives dramaticly decreases by 4 orders of magnitude.It maybe caused by the rotation of chemical structure without the restriction of β-barrel.Therefore,how to learn from nature,improve fluorescent efficiency of GFP chromophore’s deveriatives and expend its application in biomedicine is still a great challenge.We designed and synthesized fluorescence moleculars with different structures based on GFP chromophore and discussed the appliacation in bioimaging.This work is divided in the following three aspects:1.One is the modification of molecular structure.We modificated the molecular based on GFP chromophore.A serial of chromophore dimers based on different conjugated linkers were synthesized and these dimer’s structure and fluorescent properties were characterized.Then the relationship between the fluorescent behavior and conjugated linkers/solvents were studied.The results indicated that their fluorescence were proved to change in different solutions;2.Anoher is rational design of carrier.Inspired from GFP chromophore of restriction induced fluorescent improvement,we grafted GFP chromophore derivative（GA）which has self-restricted effect to poly（ethylene glycol）-block-poly（N-isopropyl acrylamide）（PEG-b-PNIPAM）,the amphiphilic polymer,and obtained PEG-GA-PNIPAM,PEG-PNIPAM-GA with GA located in the middle or end of the polymer.The self-assembly behavior and fluorescent intensity could be adjusted by variation of temperature.The structure and fluorescent properties were fully characterized.And the results showed that PEG-GA-PNIPAM and PEG-PNIPAM-GA showed different fluorescence properties in water and THF;3.Fluorescences of PEG-GA-PNIPAM and PEG-PNIPAM-GA in L929 cells and MCF-7 cells were also studied.The results showed that PEG-PNIPAM-GA exhibits much stronger fluorescence than PEG-GA-PNIPAM in MCF-7 cells and is located mainly in cytoplasm.PEG-PNIPAM₇₄-GA enters L929 cells and MCF-7 cells incubated in DMEM（10%FBS）more easily compared with Cell Tracker^TM Red CMTPX.Thus,PEG-PNIPAM₇₄-GA has the potential in bioimaging.