Fluorescent Polynorbornenes Based On Ring-opening Metathesis Polymerization For Ion Recognition And Cell Imaging

The fluorescent polymers of norbornene have been widely studied for ion recognition and bioimaging,but their poor water solubility has limited their application in aqueous phase and in vivo.In order to obtain water-soluble norbornene polymers,this thesis,on the one hand,the introduction of water-soluble group polyethylene glycol in the side chain of poly(norbornene)allows the polymers to possess a good water solubility,and the polymers can form nano aggregation by self-assembly methods,on the other hand,obtains water-soluble fluorescent nanoparticles were obtained by physical encapsulation of surfactants with good bio-solubility.The application of polymeric nanoparticles for ion recognition and fluorescence imaging is investigated in detail as follows.1.An amphiphilic dimeric copolymer,P-NB-AQ-PEG,was designed and synthesized,which was obtained by ring-opening metathesis polymerization of the water-soluble group polyethylene glycol-modified norbornene monomer NB-PEG and the fluorophore aminoquinoline functionalized monomer NB-AQ.The dimer copolymer is amphiphilic and can self-assemble in water to form nanoaggregates.Moreover,both NB-AQ and P-NB-AQ-PEG are able to recognise metal ions in Tris-HCl(p H=7.4)buffer solutions,showing in particular a high selectivity and a significant ratiometric fluorescence response for Zn²⁺and Cd²⁺.Based on Job curves,the complexation ratios of both sensors to Zn²⁺and Cd²⁺were determined to be 1:1.In addition,the complexes NB-AQ-Zn²⁺and P-NB-AQ-PEG-Zn²⁺were synthesized by complexing fluorescent chemosensors with metal ions respectively which responded successfully to ATP via a fluorescence burst effect and have a good specifity.Finally,P-NB-AQ-PEG shows good photostability and has been successfully applied for live cell imaging of Zn²⁺and ATP.2.Water-soluble near-infrared(NIR)fluorescent dyes have a significant meaning in cell imaging.We have synthesized a tetraphenylene modified perylidene diamine red light emitting homopolymer P-NB-PDI-TPE by ring-opening metathesis polymerization,which has good thermal stability and typical AIE properties.The water-soluble fluorescent nanoparticles P-NB-PDI-TPE-F127 were physically encapsulated by co-precipitation using surfactant F127 and characterised by dynamic light scattering(DLS),Zata potentiometry and scanning electron microscopy(SEM).The nanoparticles exhibited near-infrared emission around 645nm and good biocompatibility and were successfully used for cell imaging.