Aggregation-induced Emission Conjugated Polymers And Their Applications In Biological Imaging And Disease Theranostic

Conjugated polymer-based fluorescent probes possess excellent properties such as good photothermal stability,effcient light-harvesting ability,strong modification,high reactive oxygen species(ROS)generation efficiency and good biocompatibility,making them has broad applications in chemical sensing,biological imaging and photodynamic therapy.However,the fluorescent intensity of conjugated polymers will decrease in aggregate state,which limits their further application in biomedicine at some degree.In recent years,the aggregation-induced emission(AIE)luminescent materials have become a hot topic in the research of luminescent materials due to their remarkable enhancement of fluorescence intensity in the aggregate and solid states.Therefore,the construction of novel AIE conjugated polymers has the unique optical properties of AIE material,but also preserve the advantages of conjugated polymer,which will overcome the limitation induced by aggregation caused quenching.As a result,AIE conjugated polymer have have great potenial in biological sensing and imaging,disease diagnosis and treatment.In this thesis,a series of conjugated polymers with AIE properties were synthesized by polymerization and postmodification methods with the use of different typical AIEgens of tetraphenylethylene derivatives as monomers,and their application in photodynamic antibacterial,cell imaging,disease diagnosis and treatment were investigated.In the second chapter,a novel cationic AIE conjugated polymer was constructed by introducing electronic donor-acceptor pair into the skeleton and the modifying the uaternary.Compared to its monomer,AIE conjugated polymer possesses better light-absorbing ability and stronger ROS generation ability.Meanwhile,under the same conditions,this AIE conjugated polymer prefers to bind with microbes in the presence of mammalian cells,and shows perfect antibaterial effect via photo dynamic therapy,which holds great potential in antibacterial applications in clinic.In the third chapter,based on the previous work,we synthesized a water-soluble anionic AIE conjugated polymer via the introduction of EDTA derivatives with several carboxyl groups,which shows well chelation ability with calcium ions.This novel AIE conjugated polymer was successfully used for osteoblast specific imaging and differentiation monitoring by chelation of calcium ions in medium.In the fourth chapter,based on the AIE conjugated polymer prepared before,the drugloaded polymer nanoparticles were constructed by post-modification method.The ROS generation effect and cell uptake ability of the nanoparticles were preliminarily studied.However,the effects of dynamic therapy together with chemical therapy needs further optimization and research.