Construction Of Electrochemiluminescence Resonance Energy Transfer Biosensors Based On Metal-organic Framework Materials And Their Applications

Electrochemiluminescence（ECL）is an analysis method which combines the advantages of electrochemistry and chemiluminescence.ECL has the advantages of low signal background,high sensitivity and simple operation,which has attracted wide attention in the early diagnosis of diseases and detection of harmful substances.Electrochemiluminescence resonance energy transfer（ECL-RET）relies on the spectral overlap between the ECL spectrum of the donor and the UV-vis absorption spectrum of the recipient to achieve highly sensitive analysis of the target.Biomarker is defined as"a characteristic that has been objectively measured and evaluated as an indicator of normal biological processes,disease-causing processes,or pharmacological responses to therapeutic interventions".Biomarker is important for disease prevention and diagnosis to realize the accurate detection of a kind of important biomarker whose concentration increases or decreases in serum,tissue or saliva,which can indicate the disease state.Metal-organic frameworks（MOFs）have the advantages of permanent pores,special surface area,customizable pore size/structure,multifunctional modifications and biocompatibility.Because of these chemical and physical properties,they are of great interest to researchers as sensitive platforms for the construction of various probes（such as antibodies,DNA,and aptamers）for biosensors.Compared with the analytical methods in the field of clinical diagnosis,which rely on large instruments,the bioanalytical method based on ECL-RET biosensor has significant advantages such as low cost,convenient operation,less sample consumption and fast analysis speed,so that it has a wide application prospect in the detection and analysis of biomarkers.In this paper,the sensitivity of the detection method is proposed from the following four aspects:（1）Using the ECL-RET strategy.（2）Synthesize luminophore materials with excellent propertie.（3）Using the promoting effect of co-reaction accelerator.（4）The luminophore and co-reactive agent are combined as a whole to accelerate the electron transfer rate and reduce the energy loss.Based on the above ideas,biosensors for the detection of biomarkersβ2-microglobulin（B2M）,amyloid-β（Aβ42）and neuro specific enolase（NSE）were constructed.Specific research contents and results are as follows:1.Concentration levels of B2M can be used as an indicator of renal failure and is a promising marker for assessing glomerular and tubular function in adults.In this chapter,an ECL-RET immunosensor was constructed to detect B2M.Au@g-C₃N₄NSs has a large surface area and excellent electrical conductivity to provide excellent ECL signal.The metal-organic framework Ni Fe MOFs combined with Au NPs as quencher provides efficient ECL-RET between Au@g-C₃N₄NSs and Ni Fe MOFs.A new method for the detection of B2M with high sensitivity and selectivity was developed.The ECL intensity of the ECL-RET immunosensor decreased with the increase the B2M concentration due to the low conductivity of B2M.The linear range of the ECL-RET sensor was from 10 fg/m L to10 ng/m L,and the limit of detection was 2.3 fg/m L（S/N=3）.The developed immunosensor had high sensitivity,high specificity,and excellent stability.It could realize the sensitivity test of B2M and provide a novel idea for the detection of biomarkers.2.Aβ42 is produced by hydrolytic cleavage of amyloid precursor protein and is one of the well-known biomarkers for the diagnosis of alzheimer’s disease.A sandwich ECL biosensor based on aggregation-induced electrochemiluminescence（AIECL）was designed for the sensitive detection of Aβ42.A novel AIECL based on Ag@Zn PTC/K₂S₂O₈luminescence system is proposed.Ag NPs is used as a co-reaction accelerator to accelerate the electron transfer of ECL reaction.The ultraviolet visible absorption spectrum of Au@Ui O-66-NH₂ overlaps well with the ECL spectrum of Ag@Zn PTC.A novel ECL-RET immunosensor was developed to detect Aβ42 sensitively.Under the optimized experimental conditions,the linear detection range of Aβ42 concentration was 10 fg/m L-100 ng/m L,and the detection limit was 2.4 fg/m L（S/N=3）.The recoveries of Aβ42 were99.5-104%.The method has good stability,repeatability,and specificity.3.NSE is a specific acid protease in neurons and neuroendocrine cells,which is considered as a reliable tumor marker in the diagnosis of small cell lung cancer.In this chapter,an ECL-RET immunosensor is proposed for the ultra-sensitive detection of NSE.The co-reactive agent C₂O₄^2-and Ru（bpy）₃²⁺were integrated to form a self-enhanced ECL luminophore（Ru-Zn MOF）as an ECL donor.The carboxyl functional groups rich in Ru-Zn MOF structure can support antibody 1 through the amide reaction.Polydopamine-modified zinc dioxide nanoflowers as a double quencher of ECL recipient inhibits the ECL signal of Ru-Zn MOF.Under the optimized experimental conditions,the linear detection range of NSE concentration was 10 fg/m L-100 ng/m L,and the detection limit was 3.3 fg/m L（S/N=3）.The recoveries of NSE were 97.85%-105.5%.The method has good stability,repeatability and specificity,and provides an effective analytical tool for sensitive detection of biomarkers in early disease diagnosis.