Study Of Electrochemiluminescence Immunosensor Based On Metal-organic Frameworks Of MIL And UiO

Electrochemiluminescence（ECL）is a research method that combines electrochemical methods with chemiluminescence technology.ECL immunosensors are increasingly used in the detection of disease markers due to their advantages such as strong anti-interference,high sensitivity and specificity.In recent years,metal-organic frameworks（MOFs）materials have been widely used in adsorption,catalysis,and sensors due to their advantages such as large specific surface area,high porosity,and rich surface functional groups.This paper mainly studies the application of MOFs materials（including UiO and MIL）in ECL immunosensors.:combining MOFs with ECL luminophor(such as Ru（bpy）₃²⁺)can effectively immobilize the luminophor and greatly improve the ECL efficiency of luminophor;In addition,MOF is used as a quencher or loaded with a quencher to label secondary antibodies（Ab₂）,which is used to fabricate the sandwich immunosensors with high quenching efficiency.Therefore,the addition of MOFs has effectively improved the sensitivity and accuracy of ECL sensors for target detection.This paper mainly includes the following four parts:（1）Ru（bpy）₃²⁺-MIL-125 MOFs was directly synthesized by one-pot method,which was used as the substrate for fabricating the―label-free‖type ECL immunosensor to achieve sensitive detection of estradiol.The combination of MIL-125 and Ru（bpy）₃²⁺gives full play to the excellent ECL performance of Ru（bpy）₃²⁺and greatly improves the ECL efficiency.In addition,Ru（bpy）₃²⁺-MIL-125 with the large specific surface area contains a large number of-NH₂ functional groups,which can effectively capture and load plenty of antibodies.The detection range of―label-free‖immunosensor based on Ru（bpy）₃²⁺-MIL-125 MOFs is from0.1 pg/mL to 100 ng/m L,and the detection limit is 0.04 pg/m L.The ECL immunosensor has good stability,reproducibility and practical application.（2）A sandwich ECL immunosensor was fabricated based on the ECL luminophor silver nanoclusters-semicarbazide@AuNPs（AgNCs-Sem@AuNPs）as the substrate and MOFs material MIL-125 as the quencher labeled on the secondary antibody for sensitive detection of N-terminal pro-B-type natriuretic peptide（NT-proBNP）.AgNCs has the stable ECL signal,but the ECL response is low.Sem,as a co-reaction accelerator,can effectively improve the ECL performance of AgNCs by reacting with co-reactant potassium persulfate（K₂S₂O₈）.And the load of AuNPs can further enhance and stabilize the ECL signal.In addition,the MOFs material MIL-125 is labeled on the secondary antibody,which can effectively quench the ECL signal of the luminophor due to the resonance energy transfer between AgNCs-Sem@AuNPs（donor）and MIL-125（acceptor）.The sandwich ECL immunosensor with the good stability,reproducibility and specificity has a detection range of 0.25 pg/m L to 100 ng/mL and a detection limit of 0.11 pg/mL.（3）A competitive method-based ECL immunosensor was fabricated based on the ECL luminophor Ru（bpy）₃²⁺/UiO-67 as the marker for sensitive detection of diethylstilbestrol（DES）.The MOFs material UiO-67 has a large specific surface area,high porosity,and can fully exert its excellent ECL performance after being compounded with Ru（bpy）₃²⁺,which effectively improves the ECL luminous efficiency.Ru（bpy）₃²⁺/UiO-67 is labeled on BSA-DES to compete with DES for the active site of the antibody to fabricate a competitive method-based ECL immunosensor.The ECL signal of immunosensor was gradually decreases with the increase of the concentration of DES.The proposed immunosensor exhibited a wide linear range from 0.01 pg/m L to 50 ng/m L with a low detetion limit of 3.27 fg/mL.（4）A sandwich sensor was fabricated based on the dual MOFs materials UiO-66 and MIL-101 for sensitive detection of Aβ.The UiO-66 with large specific surface area is compounded with the luminophor Ru（bpy）₃²⁺.Ru（bpy）₃²⁺/UiO-66 as the substrate has excellent and stable ECL performance and can effectively load a large amount of antibodies.Load AuNPs on MIL-101,and then connect MoS₂ QDs（MIL-101@Au-MoS₂）via Au-S bond.MoS₂ QDs compete with Ru（bpy）₃²⁺to consume the co-reactant tripropylamine,which causes the ECL signal of luminophor to be quenched.The proposed sandwich immunosensor exhibited a wide linear range from 0.01 pg/m L to 50 ng/m L with a low detetion limit of 3.32fg/m L.