Nanoscale Metal-organic Frameworks (NMOFs) For Imaging In Cells

Metal–organic frameworks?MOFs?are crystalline three-dimensional coordination polymers composed of organic bridging ligands that are coordinatively bonded to metal ions or metal ion clusters.Its unique high porosity structural,tunable pore size and functionalization characteristics have potential applications in many fields such as gas storage,separation,catalysis,luminescence and sensing.Due to their nano-size,NMOFs possess both the properties of traditional bulk MOFs and special physical/chemical properties to show superior performance.Recent years,nanoscale metal-organic frameworks?NMOFs?have been widely applied in the field of biomedicine.In this paper,we initiated a synthetic program for the preparation of bioprobes based on nanoscale metal-organic frameworks?NMOFs?,in which the concepts of organic-based molecular sensors?OMSs?and post-synthesis modification?PSM?to introduce new functional groups combined to yield NMOF probes that are able to quickly detect some target analytes in living cells with high selectivity and sensitivity.I.In this contribution,a new redox-switchable Ui O-type of NMOF,UiO-68-ol,which was generated from the functionalized bicarboxylic acid ligand H₂L-ol and Zr?IV?salt is reported.UiO-type NMOFs have low toxicity and possess good cellular biocompatibility and membrane permeability,which allows them to be suitable forbioimaging.It can be a highly sensitive and specific fluorescence probe to detect HClO in living cells.II.We have designed and synthesized UiO-68-IS NMOFs fluorescence probe with fluorescence enhancement and"turn-on"function.Because NMOFs contains the imidazole-2-sulfur ketone functional group which has specific response to ClO^-,therefore,the nano fluorescent probe has a specificity for the detection of ClO^-.At the same time,the high specific surface area of NMOFs and the structured and porous frame structure give the NMOFs nanofluorescence probe a high sensitivity.By using this NMOFs nanofluorescence probe,we realized the fluorescence detection of ClO^-in the simulated biological environment.III.The transition from UiO-68-NH₂ to UiO-68-NCS single crystal to single crystal was achieved based on the strategy of covalent post-synthetic modification.The transition was characterized by means of NMR,IR,PXRD and elemental analysis.The modified UiO-68-NCS has a wider range of modifiable forms that allow it to be covalently linked to molecular Rhodamine 6G fluorescent dyes and enable the detection and imaging of Hg²⁺in vivo.The results prove that:Nanoscale metal organic framework NMOFs can be applied not only to fluorescence detection of chemical systems,but also biological systems to cell imaging,because of its super high specific surface area,ordered porous structure and good biocompatibility.NMOFs has high sensitivity and selectivity as a nanofluorescence probe.