The Synthesis And Characterization Of The Antibacterial Materials Based On The Metal-organic Frameworks

The drug resistance of bacteria has been becoming the big challenge for the therapy of bacterial infections due to the abuse of antibiotics,which makes the development of non-antibiotic antibacterial agents more and more important.Metal-organic frameworks(MOFs)are mesoporous materials composed of metal clusters or metal ions and polymers.Thanks to their advantages,such as porous structure,controllable composition and easily-modified surface,these materials have already been widely used in many fields.PCN 224 and Prussian blue are two kinds of biosafety MOF materials.In this thesis,several kinds of effective antibacterial agents based on MOF-PCN 224 and Prussian blue have been designed and tested.At the same time,the relationship between the material structure and function was explored,and the antibacterial mechanism of these materials were also revealed.The details are listed as following:Firstly,the PCN 224 was modified using the method of Cu²⁺doping.Cu²⁺could be introduced into the porphyrin ring of the polymer linker in PCN 224 through Cu-N bond.When a proper amount of Cu²⁺was introduced,the doped Cu²⁺could trap the photo-induced electron,hinder the recombination of electron-hole pairs,and finally enhance the photocatalytic property of the modified MOF.At the same time,the photothermal property of MOF was also enhanced.This was because the Cu²⁺could transfer light into heat through the d-d transition.Thus,through a simple Cu²⁺doping method,the antibacterial property of PCN 224 was enhanced.Secondly,the PCN 224 was modified with polydopamine.Polydopamine owns ring structure,and could interact with the polymer linker of PCN 224 through?-?interaction.Because of the subsequent electron and charge transfer between them,the energy band gap of modified MOF decreased,leading to the enhanced photocatalytic property.The polydopamine could also enhance the nanoparicles'photothermal property.And the more heat produced was able to enhance the transportation and the indirect transition of carriers,resulting in the improved photocatalytic property.In this way,the antibacterial property of the material is significantly enhanced.Thirdly,the Prussian blue was combined with molybdenum sulfide(MoS₂)to develop functional hybrid materials.Prussian blue could produce heat under 808 nm light irradiation.While the MoS₂ could produce free radical under 660 nm light irradiation.When the MoS₂ was modified with N doping carbon dots,the N doping carbon dots could transfer the photo-induced electrons,hinder the recombination of electron and hole,and improve the photocatalytic property of MoS₂.When the Prussian blue was mixed with N doping carbon dots modified MoS₂,the hybrid material could be triggered by 660 nm and 808 nm dual light to kill bacteria rapidly.Lastly,the Prussian blue nanoparticles were mixed with quaternary ammonium and carbon-carbon double bond modified chitosan to synthesize hydrogels though free radical polymerization.The Prussian blue nanoparticles acted as photosensitizers and crosspoints.The electropositive surfaces of hydrogels were able to capture the bacteria and make the bacteria inactive.When the hydrogels were exposed to 808 nm light and heated up,the captured bacteria were rapidly killed.This research provides new insight for developing broad-spectrum antibacterial agents,which are convenient,efficient and safe.This research also promots the development of new MOF-based antibacterial agents in the field of bacteria killing and wound repair,and the experimental basics and theoretical basis are also provided.