Fabrication And Synthesis Of Fluorescent Polymeric Nanopaticles With Aggregation Induced Emission Properties And Applications In Cell Imaging

Aggregation induced emission(AIE)is a peculiar phenomenon accidentally discovered by Tang's group in 2001 while studying a special dye.Different from traditional ACQ(Aggregation-caused quenching)dyes,the fluorescence intensity of these dyes is often weak when they are dispersed in dilute solution,but stronger when they are aggregated or in solid state.Due to the excellent aggregation-induced emission luminescence properties,these AIE dyes have attracted a lot of attention,and have been widely used in chemical sensing,electroluminescence,circular polarization luminescent materials,biological imaging,drug carrier,light-stimulation-responsive materials,ion detection and so on.The main work of this paper is to synthesize different kinds of small fluorescent dye molecules with active amino terminal and AIE properties Using hexachlorocyclotriphosphadene,a small molecule with high reactivity,as a cross-linking agent,amphiphilic AIE polymers with both hydrophilic terminal and hydrophobic dyes were synthesized by a cross-linking reaction between the AIE dyes with pre-synthesized hydrophilic molecules with good water dispersion.In the second chapter,TPE-CHO which can emit blue fluorescence was synthesized by simple substitution reaction,and further condensation reaction was carried out to synthesize AIE dye TPE-NH₂with an active amino terminal.After cross-linking with NH₂-PEG-NH₂through ultrasonic irradiation and hexachlorocyclotriphosphadene,the amphiphilic AIE fluorescent polymer was obtained.And characterization results show that this kind of amphiphilic AIE polymer not only has excellent fluorescence properties,anti ACQ fluorescence characteristics,at the same time,can also self-assembly for spherical nanoparticles,in the water phase dispersion,with good biocompatibility and low cytotoxicity,has extensive application prospect in the areas of biological imaging.Paper in the third chapter is directly prepared from natural high polymer chitosan as a matrix.AIE dyes TPA-NH₂,prepared in advance,grafted side chain of oxidative degradation of chitosan by hexachlorocyclotriphosphadene.Amphiphilic fluorescent chitosan was obtained,can self-assembly with good water dispersibility in water and possess superior fluorescence properties.On the other hand,chitosan itself has the characteristics of the antimicrobial properties and low toxicity.Based on these,WS-CS-TPA has good biocompatibility,low biotoxicity,and can emit bright green fluorescence in cells.In the fourth chapter,near infrared AIE dyes ATPHE were introduced,after the crosslinking reaction with amination of MPEG via hexachlorocyclotriphosphadene,to prepare the AIE fluorescent polymer which can emit bright red fluorescence.Noise interference from cells such as autofluorescence can be reduced by its large stokes displacement and the emission wavelength of the near infrared area.At the same time,the emission light from the long-wavelength has less damage to cells,so it has low cytotoxicity and better fluorescence performance,which can be used in many biological applications such as cell imaging.