Novel Electrochemiluminescence System Of Metal-Organic Gels For Sensitive Detection Of Biomolecules

The electrochemiluminescence ?ECL? analysis method combining electrochemical and chemiluminescence has many advantages such as high sensitivity,simple equipment and low background signal,and has become one of the indispensable methods in the field of analysis.Among them,the bipyridyl/tripropylamine(Ru?bpy?₃²⁺/TPrA)system and the luminol/hydrogen peroxide?luminol/H₂O₂?system are the most widely studied combinations of ECL illuminants and co-reactants.However,because of the ease of volatile and acute toxicity of TPrA,the instable luminescence and signal attenuation of luminol,and other issues greatly limit their applications.In recent years,with the development of nanotechnology,more and more researchers have begun to focus on the development of electrochemiluminescence systems using nanomaterials as ECL illuminants and ECL co-reactants,and further expand biosensing application based on these nanomaterials.However,most of the new illuminants or co-reactant nanomaterials reported so far are more complicated and complicated to synthesize.Therefore,the development of simple synthetic nanomaterials and applying them in the ECL field are promising research contents.This paper is devoted to the development of metal-organic gels?MOGs?soft materials in the field of ECL,and explores its luminescence mechanism and its application in biomolecule detection.The specific content includes the following three parts:1.Novel electrochemiluminescence system using terbium?III?metal-organic gels as the emitter for the detection of tetracycline.Mixing terbium ions(Tb³⁺)and4'-?4-carboxyphenyl?-2,2?:6?,2??-terpyridine?Hcptpy?at room temperature can obtain the new cathode luminescent ECL illuminant material:terbium organic gels?TOGs?.When the electrochemical scanning range is set from 0 V to-2 V,potassium persulfate?K₂S₂O₈?is used as a co-reactant,and the TOGs produces a strong cathode ECL signal.Mechanistic studies indicate that the ECL luminescence of the system is attributed to the external co-reactant pathway and intrinsic antenna effect-induced enhanced electrochemiluminescence?ECL?.The constructed system was used to quantify tetracycline with a linear range of 0.1?M–25?M and a limit of detection of 32.4 nM.2.TOGs are used as the electrochemiluminescence detection platforms for the detection of microRNA-141.The dopamine molecule?DA?is covalently linked to the carboxylated DNA,and the DNA nanostructure is obtained by double-cycle amplification by the enzyme-free hybridization chain reaction?bHCR?.The TOGs and gold nanoparticles?Au NPs?were modified on the electrode as a detection platform,and the nucleic acid was modified to the surface of the electrode by adding the DNA nanostructure.Since DA can effectively annihilate the signal of TOGs,the modified DNA nanostructure can also produce quenching effect,and the detection range of the target microRNA-141 is 0.5 fM-500 fM,the limit of detection is 0.18 fM.3.Silver-based metal-organic gels as novel coreactant to construct a new electrochemiluminescence system for the detection of target DNA.The amino-rich melamine and Ag⁺are mixed and heated to obtain the silver-based metal organic gels?Ag-MOGs?,a novel anode ECL coreactant material.Ag-MOGs can enhance the ECL signal of Ru?bpy?₃²⁺by about 40 times when the electrochemical scan range is 0 V to1.2 V.Mechanistic studies indicate that the reason why Ag-MOGs can enhance the ECL signal of Ru?bpy?₃²⁺is that its rich amino group can produce electrocatalytic effect on Ru?bpy?₃²⁺.The constructed system was used to quantify target DNA with a linear range of 10 fM–2.5 fM and a limit of detection of 3.2 fM.In summary,this study uses metal organic gels as the core materials,and electrochemiluminescence as the main technical means to reveal the ECL properties of MOGs,and successfully applied to the detection of biomolecules.The experimental results show that the application of metal organic gels materials in the field of ECL greatly expands its research scope and enriches the selection of new materials for ECL.