The Application Of Fluorine-containing Metal-organic Framework Nanoparticles In Nuclear Magnetic Resonance Imaging

With the changes of the times and the development of science and technology,cancer caused by environmental pollution,unhealthy diet,infection and other reasons has become the main source of population reduction.The most important early diagnosis of cancer is MRI.In clinical practice,¹H MRI technology based on ¹H atom is at the core of MRI technology.However,there are a lot of interference signals from water in vivo,so it still has the disadvantage of low signal-to-noise ratio.In recent years,people are more and more interested in fluorine NMR because of its close magnetic properties to hydrogen,higher signal-to-noise ratio and more sensitive chemical shift.Metal organic framework（MOF）nanoparticles are porous materials formed by self-assembly of organic linkers and transition metal ions.They have great potential in biomedical applications because of their large surface area,high porosity and abundant metal active sites.This paper mainly includes the following contents:first,we designed a ¹⁹F MRI probe based on UiO-66.By studying its decomposition rate,NMR fluorine spectrum,transverse relaxation time and other related properties,it is confirmed that it is stable in neutral and alkaline conditions,but in acid conditions,it will decompose to produce free fluorine-containing molecules to enhance its ¹⁹F MRI effect.The biocompatibility of the material was proved by the experiments of cytotoxicity and hemolysis.Secondly,based on the first part,we dope manganese by in-situ deposition,which not only has the characteristics of ¹⁹F MRI of pH response change.In addition,after glutathione was added,we found that the T₁ imaging performance of ¹H MRI was greatly enhanced through the longitudinal relaxation time and imaging experiments,indicating that the material is a successful ¹H/¹⁹F dual-mode imaging agent.All of these provide new ideas for the application of metal organic framework.