Synthesis Of Far Red/Near-Infrared Fluorophores With Aggregation-Induced Emission Characteristics And Their Application In Photodynamic Therapy

The development of organic fluorophores with efficient solid-state emissions or aggregated-state emissions in the red/near-infrared(FR/NIR)region is still challenging.Among the fluorescent(FL)materials,FR/NIR fluorophores(?=650–900 nm)play a crucial role in FL bioimaging.Recently,FL fluorophore with aggregation-induced emission(AIE)characteristics have captivated much interest because they provide a straightforward solution to the problem of aggregation-caused quenching(ACQ).The AIE luminogen(AIEgen)is widely used for FL bioimaging and biosensors.Photodynamic therapy(PDT)is a non-invasive therapeutic modality that has been used for the treatment of cancers.The therapeutic effect of PDT is greatly influenced by the location of photosensitizers(PSs)inside cells,hence,it is important to delivery PSs toward subcellular organelles.Mitochondria is regarded as the powerhouse for cells.The reactive oxygen species(ROS)can cause the damage of mitochondria at the early stage of PDT treatment,give rise to cell apoptosis and death.In this thesis,we reported a series of AIEgens emit at FR/NIR regions with high fluorescence quantum yield in aggregated-state and solid state,the fluorophores 4 and 5 exhibit high solidstate FR/NIR emissions with excellent quantum yields of 0.49 and 0.43,respectively.Moreover,these AIEgens are able to generate ROS efficiency under light irradiation.Herein,we fabricate a new AIE copolymer based on the cross-linkable AIE monomer(AIEM)with HPMA and AEMA.The copolymer was decorated with triphenyphosphonium(TPP)which is employed as the mitochondria-target group,and then fabricated AIE nanoparticles(NPs)for further effective PDT and imaging in malignant tumor cells.AIE NPs are excellent PSs with the expectation to target mitochondria,harvest FR/NIR emission for bioimaging and with high ROS quantum yield of 77.9% under light irradiation.In the future,these NPs,with an implantable lowpower LED excitation source,are promising therapeutic candidates for cancer treatment.