| Electrochemiluminescence immunosensor is developed by the combination of electrochemiluminescence(ECL)technology and immunoassay,with the advantages of simple operation,easy control,rapid detection,low background signals,good selectivity and high sensitivity,which shows great potential in the field of clinical analysis.When co-reactants are introduced into this ECL system,the ECL signal could be signif icantly enhanced,and the sensitivity of the sensors could be effectively improved.However,the traditional ECL systems are mainly based on intermolecular interactions between luminescent agents and co-reactants,which have some drawbacks of long distance for electron transfer,high energy loss and poor stability could increase the operation difficulty and measurement error,and could greatly limit the application of ECL system.Therefore,great attention for researchers has been attracted in improving the reacted efficiency of co-reactants.Based on this,a variety of self-enhanced Ru(II)complex are synthesized by using tris(4,4'-dicarboxylicacid-2,2'-bipyridyl)ruthenium(II)dichloride(Ru(dcbpy)32+),one derivatives of tris(2,2'-bipyridyl)ruthenium(II)dichloride(Ru(bpy)32+).Due to these self-enhanced Ru(II)complex contain two parts of luminescent reagents and co-reagents,them were called self-enhanced Ru(II)complex,and which can get high ECL signal through intramolecular catalytic.Furthermore,in this thesis,in asistance of nanotechnology,a series of ECL immunosensors are contructed for high sensitive detection of a variety of disease-related proteins.The studies of this thesis are mainly divided into the following sections:1.The research on the self-enhanced electrochemiluminescence immunosensor based on the self-enhanced Ru(II)complex functionalized porous six arrises column nanorodsThe signal amplification of traditional ECL systems are mainly based on intermolecular interactions between luminescent agents and co-reactants.However,the intermolecular interactions between luminescent agents and co-reactants have some disadvantages of long electron transfer path and high energy loss.In this work,a new self-enhanced Ru(II)complex was prepared by crosslinking reaction between Ru(dcbpy)32+ and L-Lysine(L-Lys).The self-enhanced Ru(II)complex has high luminous efficiency by intramolecular interactions between luminescent agents and co-reactants,which shorten the distance of electron transfer,reduce energy losses.Based on this,a self-enhanced ECL immunosensor was successfully fabricated for the detection of carbohydrate antigen 15-3,which showed excellent performance in the range from 0.05 U/m L to 120 U/m L with a detection limit of 0.014 U/m L(S/N = 3)and a correlation coefficient of R = 0.9977.Moreover,the prepared ECL immunosensor had good stability,excellent selectivity and satisfactory reproducibility.2.The research on electrochemiluminescence immunosensor based on the signal amplification effect of p L-Cys toward the self-enhanced PEI-Ru(II)complexIn order to further improve the luminescence efficiency of Ru(II)complex making the ECL technology to better apply in clinical analysis.Herein,the polymer L-cysteine(p L-Cys)was selected as a co-reactant of the self-enhanced Ru(II)complex to further improve the luminous efficiency.Firstly,a new self-enhanced Ru(II)complex was synthesized via amide reaction between Ru(dcbpy)32+ and polyethylenimine(PEI),then the light-emitting species(PEI-Ru(II)*)was formed based on intramolecular electron transfer between PEI· and Ru(III),which could efficiently amplify the ECL signal of Ru(dcbpy)32+.Secondly,the polymer L-cysteine(p L-Cys)film was fabricated on the glassy carbon electrode by cyclic voltammogram,which acted as a co-reactant of the self-enhanced Ru(II)complex could react with PEI-Ru(III)to generate the excited state PEI-Ru(II)* further amplifying the ECL s ignal.With the dual signal amplif ication factors,the prepared ECL immunosensor exhibited great advantages in simplif ication,rapidity,stability and selectivity.Furthermore,the linear range for the determination of carcinoembryonic antigen was from 0.10 pg/m L to 80 ng/m L with a correlation coefficient of 0.9942 and a detection limit of 0.045 pg/m L(S/N = 3).3.The research on electrochemiluminescence immunosensor based on dual quenching of the self-enhanced Ru(II)complex by folic acid and in situ generated oxygenThe drawbacks of some quenching reactants in unstablity and difficulty in labeling limit the application scope of ECL system.In view of this,this work not only using enzyme-catalyzed reaction to in situ generate quenching reactants around the electrode surface to resolve this problem,but also using nanomaterials as mimicking enzyme to overcome drawbacks of native enzyme,for instance easy deactivation and harsh reaction conditions.Besides,in this work,a new self-enhanced Ru(II)complex was synthesized via crosslinking reaction between Ru(dcbpy)32+ and polyamidoamine(PAMAM)dendrimer,and immobilized them on the surface of electrode by using Nafion,which shorten the distance of the luminous reagent between the electrode and greatly improved luminous efficiency.Firstly,the obtained Pt Cu3 alloy NCs with hollow structure could load a large number of glucose oxidase-folic acid(GOD-FA)complex,and FA oxidized the excited state PAMAM-Ru(II)* to PAMAM-Ru(III)making the ECL signal quench.Secondly,in the presence of glucose,GOD catalyzed the oxidation of glucose to produce hydrogen peroxide(H2O2),and Pt Cu3 alloy NCs as horseradish peroxidase mimetic enzyme catalyze H2O2 to in situ generate O2,which leading to the ECL signal further quenching.Finally,a sensitive electrochemiluminescence(ECL)immunosensor was constructed for cardiac troponin I(c Tn I)detection by dual quenching effect of folic acid(FA)and in situ generating oxygen(O2)toward the self-enhanced Ru(II)complex.As a results,the proposed ECL immunosensor for the determination of c Tn I exhibited a wide linear detection range of 0.1 pg/m L to 0.2 ng/m L and a low detection limit of 12 fg/m L(S/N = 3). |
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