Design,Synthesis And Application Of Fluorescent Probes For Tumor Markers Aminopeptidase-N And Hydrogen Peroxide

Fluorescent probes are now popular among researchers,mainly due to their advantages of of easy operation,low cost and in vitro detection.In particular,it can be combined with imaging technology to achieve non-invasive detection of cells and tissues,making this technology widely used to monitor the physiological processes of cells,and providing great convenience for the initial diagnosis of diseases.Recent years,cancer has become the main reason of human death.Previous reports demonstrated that aminopeptidase N（APN）and H₂O₂ are two important cancer biomarkers in clinical.Considering the advantages of fluorescent probes and the great significance of APN and H₂O₂,here in this dissertation,two fluorescent probes for the detection of APN and H₂O₂,respectively,have been fabricated.And their application in the early diagnosis and treatment of cancer was also investigated.The main results are as follows:1.A near-infrared fluorescent probe（DCMAPN）was constructed by using dicyanomethylene-4H-pyran（DCM）as the fluorphore and alanine as the recognition site of APN.The fluorescence of the probe（DCMAPN）can be efficiently quenched by the strong electron-withdrawing amide group formed in the probe.However,after incubation with APN,the amide group can be cleaved,resulting in highly emissive product DCMN with a NIR emission at 660 nm.The probe DCMAPN displayed high specificity toward APN,without interference from common metal ions,amino acids,reactive oxygen species and enzymes.It also exhibited high sensitivity toward APN,with a detection limit of 0.18 ng m L^-1.Considering that APN is highly expressed in various cancer cells,probe demonstrated high potential for the application in the early diagnosis of human cancer in clinic.2.Based on the specific reaction between borate and H₂O₂,an AIE-active fluorescent probe（TPECNPB）was designed and synthesized for imaging of H₂O₂.With a pyridinium pendant in the probe,TPECNPB is weakly emissive in aqueous solution,due to the fast intramolecular motions that decayed the energy of the excited state.While after reaction with H₂O₂,TPECNP with poor water solubility is generated and thus aggregation will occur and the intramolecular motion is restricted,resulting in strong emission.The probe has a larger Stokes shift（175 nm）,superior photo stability,and strong specificity for H₂O₂.In addition,the probe can target lipid droplet to detect H₂O₂.At the same time,the product of the reaction between the probe and H₂O₂ can effectively generate reactive oxygen species,and photo dynamically kill cancer cells.The probe is expected to be a fluorescence imaging-mediated photodynamic diagnostic reagent for cancer.