Preparation Of Near-infrared Fluorescent Quantum Dots Based On Semiconductor Polymers And Biological Imaging Research

With the development of scientific and technological research,fluorescence imaging technology changes rapidly and is widely used in bioprobe,drug delivery,particle tracking,fluorescent labeling and other fields.However,due to the maturity of technology,the development of fluorescence technology has shifted from instrument upgrading to the development of fluorescent materials.Semiconductor polymer fluorescent quantum dots stand out due to their high brightness,high sensitivity,good photostability and good biocompatibility.However,in the pursuit of multiple detection and near-infrared detection,the polymer suffers the self-quenching phenomenon,showing low fluorescence quantum efficiency,which greatly limits the development of quantum dots.Guided by molecular design,this paper designs a tetraphenylene with a near-infrared emissive 9,9-di-n-octyl-thieno-naphthothiadiazole-thiophene repeating unit as the main component and has an aggregation-induced luminescence effect(AIE effect).Ethylenebenzothiadiazole-9,9-di-n-octylfluorene act as a side chain,and it is combined with donor polyfluorene.The ratio of the near-infrared emitting units in different proportions is controlled by Suzuki polymerization,which are 2% and 4%,respectively.We synethesize two multi-emission two-color cross-polymer and named them with PTPE-DTNT2,PTPEDTNT4.Then polymerized them with a polystyrene maleic acid compound to synthesize polymer fluorescent quantum dots at a mass ratio of 1:4 to study quantum dots the Optical properties,AIE effects and temperature sensitivity,and applied to cell non-specific experiments,cell-specific labeling experiments,cytotoxicity experiments,bio-visible toxicity experiments.The two-color polymer fluorescent quantum dots prepared in this paper have been tested to have a good AIE effect,which overcomes the self-quenching problem of quantum dots.The emission peak in the near-infrared band is 716 nm,and the fluorescence quantum efficiency reaches 26.3%,31.8%in the near-infrared region,respectively.Compared with the previous Pdots,the quantum efficiency of the nearinfrared polymer in the near-infrared region is improved by nearly ten percentage points,which is the most quantum efficiency in the near-infrared region.The synthesized polymer exhibits the characteristics of two-color emission in the emission spectrum and exhibits the characteristics of two-color simultaneous labeling in biological experiments.The specific and non-specific experimental applications in biological experiments indicate that the prepared polymers have broad prospects for reference in the direction of bioluminescent probes.