Synthesis And Bioactivity Of Transition Metal-doped Nano Zeolitic Imidazolate Frameworks

Metal organic frameworks(MOFs) generally have high porosity,facil synthesis conditions,good thermal stability,discrete and ordered structure,ultra-low density,large internal surface area and other special physical and chemical properties which provide great hope for a wide range of applications,such as gas storage and separation,heterogeneous catalysis,magnetic and luminescent materials,drug delivery and antimicrobial materials.Research on MOFs has been going on for more than a decade,and the number of literature research in this area is increasing year by year.However,it is foreseeable that the development of new applications is still an important issue for MOFs research.Based on the current research status and development trend of MOFs,the synthesis of nano-MOFs materials doped with different metals and their bioactivity,including microbial antimicrobial activity and cytotoxicity,are still necessary to be studied.In the thesis,we synthesized a variety of transition metal ions doped zeolite imidazolate frameworks and tried to understand the relationship between the composition,structure of MOFs and its biological activity.This thesis mainly done the following work:(1)Synthesis of ten different metal-doped zeolite imidazolate frameworks(M/ZIF-8).Specifically,ZIF-8 materials doped different silver(the molar ratio of 5%,10%,25%,50%)and other different metalssamples are nano-sized particles and possess good crystal shape,uniform morphology and particle size.(2)The antimicrobial properties of the synthesized nano-MOFs were studied.We tested the antibacterial activity against Escherichia coli(Gram-negative bacteria)and Staphylococcus aureus(Gram-positive bacteria),respectively.The results of the above tests were analyzed and compared.The results show that the synthesized MOFs have the ability to inhibit and kill both bacteria at a certain concentration.The effects of different nano-MOFs on their antibacterial properties were studied.The results show that the modified MOFs exhibit antibacterial properties compared with the main ZIF-8materials,The antibacterial properties of MOFs doped with silver and nickel were significantly enhanced at smaller concentrations,and the antimicrobial properties of MOFs doped with cadmium were also enhanced at larger concentrations.These results indicate that the antibacterial properties of the metal-doped ZIF-8framework material are closely related to their composition.(3)Cytotoxicity of different metal-doped ZIF-8 frameworks.We used human hepatoma cells(Hep G2),cervical cancer cells(He La)and rat stem cells(3A)as models of cancer cells and normal tissue cells in vitro,and the in vitro cytotoxicity of the synthesized M/ZIF-8 was studied.The results show that M/ZIF-8had no inhibitory or lethal effect on cancer cells and normal cells at low concentration,and only show high cytotoxicity at higher concentration.In this thesis,a series of nano-sized MOFs doped with different metal ions were synthesized at room temperature.The results of antimicrobial experiments and cytotoxicity show that these MOFs had some antibacterial activity and had good cell compatibility at a certain concentration.The metal-doped ZIF-8frameworks of some metal ions(such as Ag,Ni,etc.)have a significant increase in antimicrobial activity at a small concentration and have not yet exhibited cytotoxicity.