| According to the research status of norbomene,we hope to change the limitations of norbornene derivative on probes and to further expand its application in biology.The limitations are shown in "poor water solubility" and"difficult to operate",these problems mean it can only be carried out in organic phase or semi aqueous phase difficult to operate and it can not show advantages of norbornene on structure.So,we want to further modify norbornene and break through the existing limitations in recognition,and we also expand in terms of imaging of norbornene.In this paper,both direct and indirect methods are used for the application of norbornene in ion recognition.The direct method refers to the signal and receptor are covalently linked by spacerr to get the formation of "signal-spacer-receptor";the indirect method which means IDA(Indicator Displacement Assay)refers to the indicator and receptor are binded reversibly through the form of noncovalent bond to get the formation of receptor/indicator.Both of them can transform identification information into the change of photophysical properties of signal groups(such as the increase or decrease of fluorescence;the change of color and so on.)to realize the identification of target objects.In addition,the direct method is used for the application of fluorescence imaging,which means the signal is directly linked to norbornene by covalent bond for the imaging application,such as the following.1:We synthesized norbornene derivatives NB-Az-Py and its homopolyrner P-NB-Az-Py,which includ a pyrene fluorophore group,the recognition sites of amide and triazole.We found both monomer NB-Az-Py and homopolymer P-NB-Az-Py show a good ratiometric response toward Hg(?)over other metal ions,and the in situ obtained Hg(?)complexes can be used as a secondary sensor for biothiols.The biological application of probes for the detection of Hg(II)and Cys in living cells is discussed.The binding mechanism between probes and guests has been detailedly investigated by UV-vis,emission spectra and 1H NMR titrations.2:We synthesized a norbornene-derived copolymer P-NB-Py-Fc-PEG containing ferrocene pyridinium and polyethylene glycol.The ferrocene and pyridinium components of the copolymer can cause the quenching of the commercial fluorescent indicator UD.The quenching micelle aggregates can released fluorescent dyes through the competition with ATP and detect it,the method we call it indicator displacement assay(IDA).In addition,we use UV-vis,emission spectra to detailedly investigate the binding mechanism between probes and guests.The morphology,size distributions and changes of the micelle aggregates of the polymers and the combination of the polymers with UD were verified by SEM and DLS.P-NB-Py-Fc-PEG also has been successfully used for fluorescence imaging according different ATP in living cells.3:We use tetrapHenylstyrene(TPE)as the starting material to synthesis the polynorbomene-derived polymer P-NB-TPE-PEG,which has the near-infrared fluorescence emission.In addition,we add poly(ethylene glycol)component to improve the water solubility of the polymer.The polymer can form self-assembly in water or buffer solution for the amphipathicity of itself.We confirm that polymers form stable homogeneous polymer photosensitizer nanoparticles in water by Dynamic Light Scattering(DLS)and Scanning Electron Microscope(TEM).The nanoparticles exhibit near infrared(NIR)emission at 620 nm.We use the singlet oxygen scavenger ABDA to prove that the nanoparticles can produce singlet oxygen under light.In addition,the capture imaging for singlet oxygen also carried out by DCF-DA in CT26 cancer cell.These experiments show the copolymer P-NB-TPE-PEG can be used for cellular imaging and photodynamic therapy.The nanoparticles can generate singlet oxygen(1O2)proved by collecting agent under under illumination for the near-infrared fiuorescence emission.In addition,P-NB-TPE-PEG has been used for fluorescence imaging toward cancer cells.The polymer also has a certain killing effect on the cancer cell of CT26. |
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