Synthesis And Application Of Functional Fluorescent Metal-organic Framework Materials

Metal-organic framework materials（metal-organic frameworks,MOFs）is a coordination polymer formed by metal ions or metal clusters and organic ligands self-assembly.It’s widely used in adsorption,catalysis,gas separation and drug transportation and other fields with its large surface area,high porosity,structure adjustable characteristics.Fluorescent metal-organic framework materials（LMOFs）,as a special branch of MOFs,not only maintain the structural characteristics of MOFs,but also have excellent and tunable fluorescence characteristics,which makes it possible to adjust their fluorescence properties through reasonable structural design,and have been widely favored by researchers in recent years.It is used in chemical sensing,biosensing and light-emitting devices.Nanoparticles are infused with functional nanoparticles（NPs）and LMOFs to obtain functional NPs/LMOFs,which not only enhance their performance,but also distribute NPs evenly into the pores of LMOFs to reduce agglomeration and improve their application performance in the environment.In this thesis,by combining LMOFs with different NPs to prepare different functionalized NPs/LMOFs,the removal and detection of antibiotics in wastewater,photothermal degradation of microorganisms in soil,and photothermal/photodynamic therapy and imaging of tumor cells were realized.（1）In the third chapter,the 4-phenyl-tripyridine ligand was used as the parent ligand,and three different functional groups（methyl,carboxyl and nitro）were modified on its benzene ring through structural design.Four LMOFs with different topological configurations were self-assembled with zinc ions.In addition,the magnetic layered tri-metallic oxide NiFeCo-LDO was introduced to synthesize functional LDO/LMOFs for the removal and detection of antibiotics in wastewater.The doping of LDO not only endows LMOFs with strong magnetism,but also greatly simplifies the recovery process.Its anion-exchange effect,large specific surface area and high porosity can also enhance the adsorption capacity in cooperation with LMOFs.The large pore size and high porosity of LMOFs can make LDO uniformly dispersed in it,reducing the impact of its agglomeration.The synthesized LDO/LMOFs can not only effectively remove antibiotics from wastewater,but also realize highly sensitive detection of antibiotics due to their excellent fluorescence characteristics.（2）In the fourth chapter,the porphyrin based metal organic framework photosensitizer PCN-224 was combined with the photothermal nano material Prussian blue（PB）,the antibacterial material silver nanoparticles（Ag NPs）and the temperature sensitive hydrogel to prepare PB/PCN/Ag composite functional hydrogel,where PB and PCN-224 form heterojunction,which can accelerate charge transfer,and the rapid separation of photogenerated electrons and hole pairs can enhance its photocatalytic performance.Under the irradiation of 660nm visible light,PB/PCN-224 can produce a large amount of singlet oxygen（¹O₂）,thus killing bacteria.At the same time,the photothermal properties of the photothermal agent PB make it produce a lot of heat under the light,and kill bacteria through the photothermal effect and photodynamic effect.In addition,the antibacterial property of Ag NPs itself also further strengthens the antibacterial property of composite heterojunction,thus obtaining composite functional materials with high antibacterial effect.Considering the toxicity and harmfulness of nano materials to human body and environment,we choose temperature sensitive hydrogel as a carrier to wrap PB/PCN/Ag composite materials.The good biocompatibility and extremely low toxicity of hydrogel can perfectly solve this problem.Moreover,the hydrogel can absorb bacteria through electrostatic action,and incorporate them into its own three-dimensional cross-linked network structure,further improving the antibacterial performance of composite hydrogel.In addition,PB photosensitizer heats up under the action of light.When the temperature reaches the phase change temperature（LCST）of temperature sensitive hydrogel,the hydrogel changes from the original liquid state to gel state,which is easy to recover and operate.（3）In the fifth chapter,the photosensitizer gold nanoparticles（Au NPs）and tetracarboxyphenyl porphyrin（TCPP）were combined with anthracyl metal-organic framework（DPA-MOF）to coat liposomes and corresponding antibodies on its surface,and a nanomotor for the treatment of tumor cells through the storage and release of oxygen was obtained.The anthracyl ligand of the selected metal-organic framework is a polycyclic aromatic derivative（DPA）,which can capture ¹O₂ and store it to form an internal peroxide（EPO）.Under the irradiation or heating conditions of ultraviolet light,EPO can convert and release oxygen（O₂）,and recover to DPA,combine it with zirconium ion to obtain DPA-MOF,and then load photosensitizer Au NPs and TCPP onto DPA-MOF to obtain composite Au/TCPP/DPA-MOF,The photosensitizer can produce singlet oxygen（¹O₂）under the irradiation of visible light,which can be quickly captured by DPA-MOF,switched to ultraviolet light irradiation,and released ³O₂,thus realizing the controlled storage and release of oxygen.The liposome with carbon nanotubes is coated on its outside,and the oxygen generated is gathered in the liposome and released into the tumor cells through the carbon nanotubes,thus forming a nanomotor with oxygen as the driving force.The antibody corresponding to cancer is modified on the nanomotor,and the diseased position of the tumor cells is reached through the antibody-antigen interaction,so as to realize the precise positioning of the nanomotor and the fixed-point release of oxygen,So as to achieve the treatment of hypoxic tumor cells.