Preparation And Application Of Electrochemiluminescence Immunosensors Based On Metal-organic Framework Composites

The electrochemical luminescence（electrochemiluminescence,ECL）refers that the material produced at the electrode passes through the electron transfer reaction to form an excited state of luminescence.Electrochemiluminescence is widely used in other fields due to their advantages of high sensitivity,wide linear range,simple instrument,time saving and low cost.Metal-organic frameworks（MOFs）are porous solids composed of inorganic vertices（metal ions or ion clusters）and organic ligands,which are widely used in drug delivery,catalysis and microfuel cells.On account of their high specific surface area,porous structure and good biocompatibility,MOFs have been used in the construction of ECL sensors to load more luminescence and biomolecules,and to improve the luminescence performance of the sensors.Cardiovascular and cerebrovascular diseases are one of the main causes of high mortality in the world.Therefore,early diagnosis of these diseases is very significant.In this paper,Ru（bpy）₃²⁺@MIL-NH₂-101（Al）,Ru（bpy）₃²⁺@HKUST-1 and other metal-organic skeleton composites are applied to construct the novel ECL immunosensors for detecting biomarkers of cardiovascular and cerebrovascular diseases,and making contributions to the early diagnosis of diseases.The main research contents are as follows:（1）In this chapter,an electrochemiluminescence immunosensor based on Ru（bpy）₃²⁺@MIL-NH₂-101（Al）was constructed.Potassium perbisulfate was used as a co-reaction agent and the ECL sensor showed strong cathodoluminescence signal,which could be used for the sensitive detection of a new thrombus marker—thrombomodulin（TM）.Ru（bpy）₃²⁺@MIL-NH₂-101（Al）nanoparticles were immobilized on the electrode to form Ru（bpy）₃²⁺@MIL-NH₂-101（Al）/GCE,and then combined TM antibody through amido reaction.Finally,the specificity between antigen and antibody was used to capture TM.In the layer-by-layer self-assembly process of TM/BSA/Ab-TM/Ru（bpy）₃²⁺@MIL-NH₂-101（Al）/GCE,the ECL signals were quenched continuously due to the blocking of electron transfer by protein macromolecules.Ru（bpy）₃²⁺@MIL-NH₂-101（Al）-ECL immunosensor has good stability,selectivity and reproducibility for the determination of thrombomodulin.The ECL signal intensity of Ru（bpy）₃²⁺@MIL-NH₂-101（Al）decreased linearly in the concentration range of 10-1×10^-5μg/m L,and the detection limit was low(8.2×10^-6μg/m L).Therefore,this study is expected to provide a good method for the detection of thromboregulatory protein（TM）.（2）In this work,a dual-signal electrochemiluminescence immunosensor based on Ru@HK composite materials and Ce₂Sn₂O₇nanocubes was proposed to achieve the sensitive detection of biomarker of acute heart failure—NT-pro BNP.Ru@HK composite materials were immobilized on the electrode and combined Ab₁-NT-pro BNP through amido reaction.The NT-pro BNP was captured by Ab₁-NT-pro BNP/Ru@HK/GCE through specific recognition of antigen and antibody.In the process,the ECL signals decreased on account of the protein macromolecules blocking electron transfer.Finally,Ab₂-Ce₂Sn₂O₇was incubated on the electrode.The sensor showed the dual signal,and the higher the concentration of antigen,the stronger the detected light signal of Ab₂-Ce₂Sn₂O₇.This dual-signal ECL immunosensor has a wide linear range(1×10^-9-1μg/m L)and a low detection limit（17.8 fg/m L,S/N=3）,and it shows high sensitivity,excellent specificity and stability.The dual-signal immunoassay platform not only reduces the false positive rate of detection results,but also provides a new method for the early diagnosis of heart failure.