Study And Application Of Fluorescent Sensors Based On Click Chemistry

Click chemistry is the reaction which synthesizes various macromolecules quickly and reliably via splicing small unit molecules.As click chemistry owns the advantages of the available reactants,mild reaction condition,nice anti-interference and high output,it has been applied in many research fields,such as surface functionalized modification,macromolecular synthesis,nanaomaterials,proteins,DNA and so on.In this paper,based on the facts that highly fluorescent triazole complex could be produced through Cu(I)catalysed alkyne-azide cycloaddition(CuAAC)reaction between the azide group and terminal alkynes,four fluorescent sensors had been developed and applied to detect actual samples with satisfied results.This paper contains five chapters.In the first chapter,the concept,type and characteristics of click chemistry were outlined.The principle,characteristics and applications of fluorescent sensors and enzyme-linked immune sensors were briefly introduced.Then,the application of CuAAC reaction in biological macromolecules,colorimetric analysis,fluorescent analysis,and electrochemical analysis were described in detail.At last,the purpose and contents of this paper were pointed out.In the second chapter,a fluorescent sensor based on click chemistry for Cu(Ⅱ)had been proposed.Cu(II)could be reduced to Cu(I)by sodium ascorbate(SA)and then triggered the CuAAC reaction between the weak fluorescent compound(3-azido-7-hydroxycoumarin)and propargyl alcohol to form a strong fluorescent compound.The liner detecting range was 0.25 μM-2.5μM with a detection limit of 0.08 μM(S/N=3).The developed sensor had been applied to detect Cu(II)in serum samples.In the third chapter,a sensitive fluorescent sensor based on click chemistry for determination of flumioxazin residue in food samples had been developed.The sensor was designed based on the formation of strong fluorescence compound(1,2,3-triazole compounds)via the reaction of the alkynyl group in flumioxazin with 3-azido-7-hydroxycoumarin.The fluorescence increased factor(represented by F/F0)of the system exhibited a good linear relationship with the concentration of flumioxazin in the,range of 0.25 μg/L-6.0 μg/L with a detection limit of 0.184 μg/L(S/N=3).The proposed fluorescent sensor had been applied to test the flumioxazin residue in some vegetable and water samples with satisfied results.In the fourth chapter,a selective fluorescent sensor based on click chemistry for the detection of ethinylestradiol which was an environmental distractor had been conducted.Ethinylestradiol has the terminal alkyne and then it can be reacted with 3-azido-7-hydroxycoumarin through CuAAC reaction.The liner detecting range for ethinylestradiol was from 0.1 μg/L to 2.5 μg/L and the detection limit was 0.05 μg/L(S/N=3).In the fifth chapter,a novel and selective fluorescent method had been designed to determine a trace level of alpha-fetoprotein(AFP).This method combined enzyme-linked immunosorbent assay(ELISA)with the CuAAC reaction.The antigen AFP and CuO-conjugated AFP antibody could sequentially bind together through antigen-antibody specific interaction,and then the Cu(II)was released from CuO by HCl and reduced to Cu(I)by sodium ascorbate(SA)to induce CuAAC reaction between 3-azido-7-hydroxycoumarin and propargyl alcohol to form a strong fluorescent compound.The fluorescence increased factor(represented by F/F0)of the system exhibited a good linear relationship with the concentration of AFP in the range of 0.025 ng/mL-5.0 ng/mL with a detection limit of 0.012 ng/mL(S/N = 3).Based on high sensitivity and selectivity,the proposed fluorescent sensor had been applied to test the AFP in human serum with satisfied results.