The Reactive Fluorescent Probe Based On Borodipyrrole Dyes And Biological Imaging Application

BODIPY dyes have been widely used in bioimaging,photodynamic therapy,laser dyes,OLEDemission materials and organic photovoltaic and other fields because of excellent photochemical and physical properties,such as convenient synthesis,good photochemical and chemical stability,high molar extinction coefficient,fluorescence quantum yield,narrow fluorescence emission peak and so on.However,traditional BODIPY dyes also have disadvantages such as single emission,short wavelength,small Stocks shifyand,less molecular combination,which limit their application in organelle,bioimaging and other optical fields.Therefore,basing on BODIPY skeleton,we modified the structure of BODIPY chromophore,and constructed a variety of large?-conjugated systems and functional molecules through reasonable molecular combination and design.Moreover,according to the specific chemical reaction of the analytes,a series of BODIPY fluorescent probes were developed to detect reactive molecules,and study their fluorescence properties and bioimaging applications.As following:1.A novel fluorescent probe BODIPY-Se for lysosomal hydrogen peroxide?H₂O₂?was designed and synthesized by the combination of selenalmorpholine unit and BODIPY fluorophore.By protonation of nitrogen atoms on selenalmorpholine and oxidation reaction of selenium atoms with H₂O₂,photoinduced charge transfer effect?PET?from nitrogen atoms to BODIPY fluorophore can be effectively inhibited,thus realizing the gradual enhancement of fluorescence signal for BODIPY-Se.Meanwhile,BODIPY-Se can realize 5 redox cycles between H₂O₂ and glutathione?GSH?.The results of bioimaging showed that BODIPY-Se could target cell lysosomes?Pearson coefficient of 0.96?and detect endogenous and exogenous hydrogen peroxide in living cells.2.A hydrogen peroxide fluorescent probe BODIPY-BQ based on oxidation-cyclization reactionwas designed and synthesized with BODIPY chromophore as the core.The borate on the 2,6-sites of BODIPY chromophore acts as the receptor,to achieve specific redox chemical reactions with hydrogen peroxide.The absorption and emission wavelengths of BODIPY dyes were significantly red-shift when the 3,5-sites of BODIPY chromophore were modified with unsaturated acrylate phenolic hydroxy esters.BODIPY-BQ can selectively and sensitively interact with hydrogen peroxide,through the oxidation-hydrolysis of borate ester,and then the transesterification-cyclization reaction,which promotes the formation of a new conjugated system of probe molecules and significantly decrease s the fluorescence of the probe.3.By Knoevenagel condensation reaction,??11??-unsaturated pyrazolinone unit was connected to the 2-site of BODIPY chromophore,and a fluorescent probe BODIPY-Pyra targeting mitochondria and selective detection for hypochlorite was designed and synthesized.The BODIPY fluorophore bridged with the pyrazolinone unit through C=C double bond,forming a twisted intramolecular electron transfer?TICT?with a weak red light.However,the increase of ambient viscosity will effectively inhibit the TICT effect and enhance the red fluorescence of the probe.In addition,BODIPY-Pyra was able to selectively and sensitively undergo redox reaction with hypochlorite by oxidative cleavage of C=C double bond with hypochlorite,and produce blue shift of uv and fluorescence of probe.Bioimaging experiments have shown that BODIPY-Pyra can direct the mitochondria?Pearson coefficient 0.97?and can also detect hypochlorite in cells and organisms.4.By Sonogashira coupling and Knoevenagel condensation reactions,naphthalimide fluorophore and unsaturated pyrazolinone structures were introduced on both sides of the BODIPY chromophore,respectively,and a hypochlorous acid/hypochlorite fluorescent probe BODIPY-Np with double recognition sites and ratiometric changes was designed and synthesized to locate in lysosomes.Because of double recognition sites,BODIPY-Np can act quickly with hypochlorous acid/hypochlorite to oxidize the thioether on naphthalimide to sulfoxide and decrease the fluorescence of naphthalimide unit.At the same time,C=C bond on unsaturated pyrazolinone was broke,the fluorescence of BODIPY core was turned on with a ratiometric change.Bioimaging experiments have shown that BODIPY-Np can locate lysosomes?Pearson coefficient 0.98?and monitor hypochlorous acid in cells and organisms.5.Through Sonogashira coupling reaction,the fluorescence platform of BODIPY-triphenylamine with intramolecular charge transfer?ICT?effect and dual-band and long-wave emission was constructed,and fluorescent probes BTN and BTB with different photophysical properties were designed and synthesized.The introduction of triphenylamine acetylene group on both sides of BODIPY chromophore leads to the obvious red shift of the emission wavelength of BODIPY dye,and presents D-A-D structure.BTN introduced four hydroxyl oxime on the periphery of triphenylamine as the receptor,which realized the multi-site,fast?10s?and specific reaction to hypochlorous acid,and presented colorimetric and ratiometric on the spectrum.However,unsaturated tert-butanol acrylate was introduced to rep lace hydroxyl oxime in the periphery of triphenylamine to obtain BTB with solid fluorescence and aggregation induced luminescence.BTB not only presents obvious ICT characteristics and solvent effects,but also has a large fluorescence emission wavelength and pseudo-stocks displacement.In dimethyl sulfoxide/water,BTB showed obvious aggregation induced fluorescence enhancement with the increase of water fraction.In addition,BTB also showed a selective reaction on cysteine,which could lead to quench the fluorescence induced by aggregation of BTB.6.By suzuki coupling reaction,the short wavelength BODIPY fluorophores and long wavelength BODIPY dyes were combined to construct a fluorescent molecule BODIPY-By with through bond energy transfer?TBET?.BODIPY-By take short wavelength BODIPY as the energy donor,long wavelength BODIPY as the energy receptor and rigid Biphenyl structure as the connecting group,presenting the property of TBET?ETE=86%?.long wavelength BODIPY dye contains a pair of??11??-unsaturated double bonds,with a certain nucleophilic reactivity.The conjugated addition reaction of BODIPY-By with cysteine/homocysteine was performed selectively with ratiometric change.Compared with cysteine,homocysteine showed a faster reaction rate with BODIPY-By.Therefore,BODIPY-By can have a selective detection of homocysteine.