Synthesis, Characterization And Application Of Cationic Phenyleneethynylene Conjugated Organic Materials

Due to the unique optical properties, good water solubility and biocompatibility advantages,water-soluble conjugated organic materials have been widely used in sensing, biological imaging,drug delivery, photodynamic therapy and so on. So it has become a research hotspot in optoelectronicinformation materials. Firstly, because the unique optical properties of water-soluble conjugatedorganic materials and good water solubility, it can be well absorbed by cells and realized cell imaging.Secondly, the excitons can be efficiently transmitted over long distances to reduce electron or energyacceptor sites, which made the conjugated organic material fluorescence quenched or acceptorfluorescence signal amplified. So it can be used as high sensitivity information sensor. Thirdly, sincethe water-soluble conjugated organic material having rigid segments and soft segments, this particularstructure determines its self-assembly behavior can occur in aqueous solution. Thereby it can be usedin entrapping drugs and drug delivery. Based on this background, a series of water-soluble conjugatedorganic materials were designed and synthesized and their photophysical properties, self-assemblybehaviors were given in this paper. Besides, PTP5with low cytotoxicity and good biocompatibilitywas applied in cell imaging.(1)A novel oligo(phenylene ethynylene)(TP1) was designed and synthesized. The studying ofphotophysical properties indicates that the TP1fluorescence is almost completely quenched withthe addition of Fe3+.And the fluorescence intensity of this TP1-Fe3+system enhanced to a greatextent when the F-was added into the with this system. So a good optical signal conversion between“OFF-ON” was realized. Fluorescence-based nature of this system can switch to build a simplechemical logic gates. Based on the fluorescent switch properties of this system, we can build asimple chemical logic gates.(2)A novel oligo(phenylene ethynylene) brush(OPEN+) was designed and synthesized withhigh charge density via atom transfer radical polymerization(ATRP).Its photophysicalproperties,self-assembly behavior (particle size, morphology) and the stability of self-assembly inaqueous solution was studied and the results show that OPEN+has self-assembly behavior inaqueous solution and form stabilized nanoparticles, which indicates that it has potential applicationsin the field of drug delivery.(3)A new type of water-soluble conjugated polymer brush(PTP5) was designed andsynthesized. Its basic photophysical properties and spectral stability under different salt concentrations and different pH conditions was studied and the results show that PTP5has goodspectral stability. Furthermore, the study of its self-assembly behavior indicated that PTP5can formstable nanoparticles in aqueous solution and the nanoparticle size can be regulated by controllingthe PTP5concentration. Finally, the low cytotoxicity of the polymer demonstrated by MTT assayexhibits its potential in long-term clinical application. Besides, this polymer could be taken up bycells easily. The results illustrate that the polymer has potential applications in the biomedical field.