The Researches On Construction Of Functionalized Metal-Organic Framework Materials And Their Applications In Optical Biosensing

Analytical sensors often use a variety of conversion mechanisms to convert the characteristics of the detected objects into electrical,optical and acoustic signals and collect them.Among them,photometric analysis uses the interaction between analyte and probes to detect the presence of analyte or target state(such as temperature),which is one of its most ideal transduction mechanisms.The key to the construction of optical analysis system is to design and synthesize new probes with sensitive optical response.As one of the potential porous nanomaterials,Metal-Organic Frameworks(MOFs)combine the advantages of inorganic and organic materials,their abundant reaction sites and functional sites has significantly improve the selectivity and sensitivity of detection in sensing field.However,there are still many challenges in building stable functionalized MOFs materials,especially in realizing fast and simple synthesis,or the functional collaboration of materials.Therefore,exploring new strategies for synthesizing stable functionalized MOFs materials is of great significance for widening the application of the materials in bio-environmental analysis.The main work of this study is to design appropriate strategies to construct NMOFs(Nanoscale MOFs)composites,and characterize the morphology,structure and properties of the materials by various characterization methods,further constructed novel biosensor system for bio-environmental analysis.The main contents of this paper are as follows: Chapter 1 OverviewThis chapter is mainly about the literature research on the status and development of MOFs materials.It mainly introduces the characteristics,advantages,design strategies,synthesis methods and their applications of MOFs materials in various fields.Based on this background,the content and significance of this research work are summarized.Chapter 2 Monitoring and Bioimaging of High Reactive Oxygen Species in Cells Based on Gold Nanoclusters Functionalized ZIF-8 Fluorescent CompositesThe level of reactive oxygen species(ROS)in living organisms is closely related to neurodegenerative diseases and Alzheimer's disease.High ROS(hROS)often cause serious cell apoptosis and tissue damage.Therefore,it is necessary to develop sensitive and efficient detection methods to monitor the level of hROS in organisms.In this chapter,we successfully encapsulated the glutathione-stabilized gold nanoclusters in the nanoscale MOFs ZIF-8,which greatly improved the luminescent properties in terms of intensity and lifetime.The composites were characterized by TEM,XRD,FTIR,BET,TGA,FL,etc.XPS results show that redox reaction between hROS and gold clusters influenced the fluorescence signal,which can be used to detect hROS.The detection limit(30 nM)of hypochlorite is 30 times lower than that of gold nanoclusters(960 nM).On this basis,we applied the composite material to the cell imaging experiment.On the premise of low toxicity,we found that the composite material has better imaging effect than the single gold nanoclusters,and more suitable for monitoring the intracellular level of hROS.Chapter 3 Iron-Modified Nano-MOFs with Peroxidase Mimetic Properties for Colorimetric Determination of Hydrogen Sulfide.The main content of this chapter is to construct Fe-NMOFs materials by postsysthesis modification(PSM).The functional materials not only retain the complete structure and porous characteristics of NMOFs,but also exhibit strong peroxidase mimetic properties after being modified by iron ions.In the presence of hydrogen peroxide,the Fe-NMOFs can catalyze the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine(TMB)to exhibit blue color,and its absorbance and hydrogen peroxide concentration are in good linear relationship,so the system is expected to be used for the analysis of biomolecules such as glucose,uric acid and NADPH.At the same time,we found that the presence of hydrogen sulfide could significantly inhibit the catalytic properties of Fe-NMOFs.Based on this,we have developed a new method for achieving highly sensitive and highly selective colorimetric sensing of hydrogen sulfide.The method has a linear range between 2.0-30 ?M and detection limit of 1.07 ?M and it was successfully applied to the monitoring of the release of hydrogen sulfide from gas messenger molecules in cell systems.