Synthesis Of Novel AIE Small Molecules And Application In The Fluorescent Detection Of CO And Labeling Of Endometriosis

In recent years,the fluorescence imaging technology is popular because of its non-invassive imaging mode.However,most fluorescent materials suffer from ACQ effect in the aggregated state,which greatly limits their biological applications.The emergence of aggregation-induced emission（AIE）molecules provide the opportunity to solve the problem that ACQ molecules face.Compared with traditional fluorescent materials,AIEgens can maintain high fluorescence emission in the aggregated states.Therefore,the development of novel AIE-active molecules for the detection and imaging of bioactive small molecules and in vivo fluorescent labeling of diseased region is of great importance and may find promising application in the clinic.Therefore,in this dissertation,we carried out the following two works:1.A reaction-based fluorescent probe（BTCV-CO）with aggregation-induced emission（AIE） characteristics was designed and synthesized for CO detection and imaging.BTCV-CO was designed based on the in situ reduction ability of CO to convert Pd²⁺to Pd⁰ and the subsequent Pd⁰ mediated Tsuji-Trost reaction.BTCV-CO is expected to be weakly emissive in solution due to the fast nonradiative decay of the singlet excited state that is facilitated by cis-trans isomerization about the C-C double bond of the alkene linker.The CO-promoted removal of the allyl group in BTCV-CO would generate the phenolate intermediate,which will undergo rapid cyclization and thus restrict the rotation of the C-C double bond to give the highly fluorescent benzithiazolyl iminocoumarin（BTIC）,which is also confirmed to be AIE-active.This ratiometric AIE probe showed excellent stability,high sensitivity （detection limit of 30.8 n M）and superior selectivity.In addition,in vitro and in vivo imaging of CO in living cells and in live mice were successfully realized by using BTCV-CO.More importantly,this CO- responsive AIE probe could be facilely designed and easily obtained by two-step synthesis with high yield,providing an easy-to-handle AIE toolbox for real-time visualization of CO in living system.2.A novel AIE-active fluorescent probe（TBZ-2TPA）with both NIR absorption and emission was designed and synthesized by using thiadiazole benzotriazole with an alkyl chain as the donor moiety linked with triphenylamine as the acceptor moiety on both sides.TBZ-2TPA is a typical molecule with donor- acceptor-donor（D-A-D）structure with strong intramolecular interactions.In order to make TBZ-2TPA capable of fluorescent labeling of diseased region,we encapsulated TBZ-2TPA with PEGylated lipid to obtain AIE dots.CAS-binding peptides which can specifically bind to the endometriosis region was conjugated to the surface of AIE dots through click chemistry.The thus obtained em CSA-AIE dots can be used to fluorescent label of endometriosis in vitro and in vivo,showing great potential in clinical diagnosis of endometriosis.