Design Of Functionalized Metal-Organic Frameworks For Detecting Biomarkers

It is of great significance to detect the content of abnormal biomolecules(considered as biomarkers)in the biological system for the clinical diagnosis and treatment of diseases.In biosensing,the development of luminescent materials that specifically detect biomarkers in complex biological fluids has become a research hotspot.Metal-organic framework(MOFs)materials have shown great application prospects in fluorescence sensing due to their abundant functional sites,large surface area and structural diversity.The MOFs sensing materials with excellent fluorescence characteristics can be constructed by rationally designing MOFs to achieve precise sensing of specific biomarkers.In this thesis,five kinds of luminescent MOFs had been successfully prepared by the in-situ doping and post-synthesis modification,respectively.The above-mentioned luminescent MOFs in fluorescence detection for biomarkers were intensively studied.The main contents of this thesis are shown as follows:1.A novel luminescent metal-organic framework based on Eu³⁺functional Al-MOF(Eu³⁺@Al-MOF)is prepared by selecting Al-MOF containing uncoordinated carbonyl groups as the parent framework,Eu³⁺ions are successfully introduced into the pores of Al-MOF by the PSM method.The obtained Eu³⁺@Al-MOF material has strong red fluorescence and excellent stability.In addition,the Eu³⁺@Al-MOF exhibits excellent analysis performance for3-methoxytyramine in urine.Considering the practical application,a fluorescent test paper is further prepared,and the color change can be observed with naked eyes,thus achieving the visual identification of 3-methoxytyramine.2.Based on the Sc-MOF material with the open pyridine nitrogen sites on the ligand,the Eu³⁺ions functionalized material Eu³⁺@Sc-MOF is successfully constructed via PSM approach.The material can be acted as a fluorescence sensor for detecting 2-hydroxyglutaric acid with high selectivity and sensitivity and fast response even in the presence of serum and urine components.Meanwhile,test papers and hydrogels are exploited as a portable platform for visual sensing2-hydroxyglutaric acid,which offers a promising approach in practical application.3.Through the in-situ doping method,Tb³⁺-NOTT-220-4 material with outstanding fluorescence performance is created by doping Tb³⁺ions into MOFs(NOTT-220)material and adjusting the doping ratio of Tb³⁺ions.According to the fluorescence emission of ligand and Tb³⁺,the material displays ratiometric fluorescence response for serotonin in serum system,and has good selectivity and sensitivity.In addition,the combination of Tb³⁺-NOTT-220-4 and hydrogels provides the possibility for practical applications.4.A fluorescent Eu/Bi-MOF with ultra-high luminescence quantum yield was synthesized by doping Eu³⁺ions into the lattice and the material dispersed in aqueous solution to form a luminescence-silent systems.With the addition of histidine,the fluorescence signal of the luminescence-silent systems gradually recovers with ratiometric fluorescence response.Meanwhile,the luminescence-silence system shows excellent analytical performance for histidine in amino acids and complex biological systems.In addition,the Eu/Bi-MOF fluorescent film provides rapid response and quantitative analysis for histidine,thereby providing a simple and convenient detection method.5.On the basis of Ga-MOF material with active carboxylic acid sites,the dual-emission fluorescent material(Ln@Ga-MOF)was prepared by introducing Eu³⁺and Tb³⁺ions into its framework.Meanwhile,a series of Eu/Tb@Ga-MOF materials with adjustable fluorescence emission were obtained by adjusting the ratio of Eu³⁺and Tb³⁺.Besides,a sensing system for ratiometric fluorescence detection of5-hydroxyindole-3-acetic acid has been established based on dual emission materials,which has the advantages of high selectivity and high sensitivity.