Preparation Of Metal Organic Frameworks (MOFs) Functional Materials And Their Applications In Biosensing Analysis

Metal organic frameworks?MOFs?materials,which are porous hybrid materials composing of metal ions and organic ligands,have been widely used in the separation,storage,catalysis,sensing,and drug delivery fields.In the present thesis,three kinds of fluorescence detection methods have been developed using different MOFs for the analysis of blood copper,water,and lanthanide ions.The contents mainly include:?1?A microarray-based fluorimetric analysis method has been developed using MOFs?ZIF-8?coated red fluorescent silver nanoclusters?AgNCs?for the detection of copper ions?Chapter 2?.At room temperature,bovine serum albumin?BSA?was first modified on the surface of AgNCs,followed by the encapsulation of ZIF-8 by protein-mediated biomineralization,yielding the AgNCs-BSA@ZIF-8 nanocomposites.It was found that the introduction of BSA and ZIF-8significantly improved the aqueous phase stability and especially fluorescence intensity of AgNCs.The so obtained AgNCs-BSA@ZIF-8 could specifically adsorb and bind with copper ions,leading to the structure collapsing and fluorescence quenching of AgNCs.Subsequently,a high-throughput fluorimetric microarray was thus fabricated by coating fluorescent composite materials onto the microwell array with hydrophilic-hydrophobic wettability,achieving the highly sensitive sensing of copper ions in the blood,showing the detection linear range of 4.0×10^-4 to 160?M.?2?Based on sodium citrate regulation,two fluorescent Cit-Tb-MOFs and Cit-Eu-MOFs functional materials were prepared as the"fluorescent ink"and especially as the fluorescent probes for the fluorimetric analysis of water content in the organic solvents?Chapter 3?.Fluorescent Tb-MOFs and Eu-MOFs were prepared through a protein-mediated biomimetic mineralization pathway using BSA as the template and sodium terephthalate as the organic ligand.Furthermore,sodium citrate was introduced to separately form Cit-Tb-MOFs and Cit-Eu-MOFs nanocomposites.It was found that the specific fluorescence quenching occurred when the nanocomposites contacted with water,whereas their fluorescence would be restored after drying,thus exhibiting the sensitive characteristics response to humidity.A high-throughput fluorimetric analysis method was developed for probing water content in the organic solvents by coating the nanocomposite materials onto the microwell array patterned with a hydrophobic substrate.Subsequently,the feasibility of the nanocomposite materials for developing“fluorescent ink”was investigated,indicating that they would be applied for the humidity control of some special substrate surfaces,trademark anti-counterfeiting,and encryption technologies.?3?A fluorescent detection technique with Zn-MOFs materials has been established for the fast measurement of lanthanide ions of Eu³⁺and Tb³⁺ions in wastewater?Chapter 4?.Under the hydrothermal reaction conditions,2,4,6-trimethyl-1,3,5-trimethyleneoxy parabenzoic acid containing multiple carboxyl groups was introduced to react with zinc ions to yield Zn-MOFs,which were used as the mesoporous functional probes with high volume-to-surface area.It was discovered that the resulting Zn-MOFs could present strong red and green fluorescence emissions once binding with the lanthanide ions of Eu³⁺and Tb³⁺,respectively.In particular,the fluorescence intensities of Zn-MOFs could depend on the concentrations of lanthanide ions that could bind with the excessive carboxyl functional groups of Zn-MOFs.Two high-efficiency fluorimertic analysis methods were thereby developed for the separate analysis of Eu³⁺and Tb³⁺ions in wastewater with detection linear ranges of 1.0 nM to 2.0?M and 1.0 nM to 50.0?M,respectively,together with a strong ability against the background interference.More importantly,the so fabricated MOFs materials may promise the potential of wide applications for the adsorption,sensing detection,and recycling of lanthanide ions.