Tetraphenylethene-Based Organic Conjugated Polymer Fluorescence Probe: Preparation, Characterization And Application

Recently,high efficient luminescent materials show great potential application values in electronics,biotechnology,medicine fields,etc..Owing to its high sensitivity,good selectivity,convenient operation,low cost,rapid response and low detection limit,the fluorescent probe has been widely applied in many fields such as biology,materials science,environmental science,information science,etc..It's also a very prominent and effective method of detecting and exploring biosystem of each important species nowdays.At present,most of the traditional fluorescence probes exhibit aggregation-caused quenching?ACQ?effect due to their poor water-solubility,biocompatibility and cell permeability.Therefore,they could not be widely used in chemical/biosensor and biological cell imaging.In this paper,several highly sensitive polymer fluorescence probes with AIE effect containing tetraphenylethene units in the conjugated backbones were designed and synthesized.These new AIE probes were applied to the detection of explosives and biological cell in vivo in aqueous media.?1?Conjugated polymer fluorescence probe P1^P3 were synthesized by homopolymerzing an AIEgen di?naphthalen-2-yl?-1,2-diphenykethene?DNDPE?itself or copolymerizing DNDPE with fluorene or carbazole derivatives.We have studied their thermogravimetric behavior,photophysical properties,electron cloud model and applications in the detection of explosives.The results show that P1^P3 have high thermal stability and the initial thermal decomposition temperature is 406⁴82?.They are weakly fluorescent in dilute solutions but become highly emissive as aggregating,displaying the aggregation-ehanced emission?AEE?feature.Picric acid?PA?can effectively quench the fluorescence of macromolecules in aqueous media,and their quenching constant K_SV are up to 1.18×10⁶ M^-1,which indicate that they have a promising application in the detection of explosives.?2?Copolymerizing alkyl chain-modified tetraphenylethene?TPE?with fluorene,benzene and benzothiadiazole respectively to obtain neutral polymers,then treated with trimethylamine to afford polymer fluorescence probe P4^+P6⁺.These new polyelectrolytes show AEE characteristics with fluorescent color covering from cyan to orange.Their utilities as bioprobes to detect HeLa cells were investigated through Confocal Laser Scanning Microscopy?CLSM?and time-resolved fluorescence measurements and imaging using the Time Correlated Single Photon Counting?TCSPC?technique.The results showed that the high molecular weight bioprobes with low cytotoxicity and good biocompatibility can enter living cells in a noninvasive manner,and the aggregated fluorescent clusters in the cells emit bright fluorescence and display different fluorescence lifetimes.In particular,a great amount of P6⁺can enter into the Hela cells exhibiting the short lifetimes predominantly situated around the inner side of cell membranes and the longer lifetimes in the cytoplasm of some cells.