Photothermal And Photodynamic Antitumor Studies Of Conjugated Organic Macromolecular Nanomaterials

Cancer has become a worldwide problem.Although traditional chemotherapy,radiotherapy and surgery have been widely used and achieved certain results,there are still some inherent defects.Photodynamic therapy and photothermal therapy are emerging cancer treatment methods,which can provide some supplements for the mainstream three therapies.These two therapies have the advantages of small side effects,strong specificity and short treatment time,so they have been focused on and studied.Photodynamic therapy is to change the photosensitizer molecules into excited states by light,and then the molecules will transfer into the triplet states with relatively low energy levels by intersystem crossing,and transfer energy or electrons to the surrounding substrate molecules,to produce biotoxic reactive oxygen species(ROS),which kill tumor cells.Photothermal therapy converts the irradiated laser energy into heat energy by using light-absorbing materials and creates a high-temperature environment in the target area,resulting in thermal ablation of tumor tissue.Conjugated organic compounds have been widely used in photothermal therapy and photodynamic therapy because of their good optical properties,biocompatibility and structural controllability,which are suitable for large-scale preparation and storage.Meanwhile,conjugated organic compounds can easily assemble into nanomaterials due to their molecular interactions,and are applied in tumor therapy.Based on the above facts,this paper studies the treatment of cancer by photothermal or photodynamic effects of nanomaterials that assembled by conjugated organic compound with high molecular weight from the following aspects:1.Diiridium(Ⅲ)complexes were assembled into nanoparticles and applied in photodynamic therapy.It was proved that diiridium(Ⅲ)complexes could also produce the photodynamic effect to kill tumor cells under low power visible light irradiation,and the photodynamic effect of nanomaterial was further studied under a hypoxic condition.2.Photothermal-induced chemotherapy of merocyanine-paclitaxel conjugated nanoparticles can destroy the nanomaterial under light and release paclitaxel derivatives,result in kill tumor cells through light response.3.The tetraphenylethylene(TPE)was combined with the diketopyrrolopyrrole(DPP)and formed a novel compound.The compound was assembled into nanoparticles and killed tumor cells by photothermal therapy.Great changes were taken place in optical properties while the compound is assembling into nanomaterials.It can be qualitatively observed that nanomaterials in tumor cells tend to be disassembled with the passage of endocytosis time.Meanwhile,the ability of the nanomaterials to kill tumor cells by photothermal was tested.4.Photothermal therapy of self-assembled nanomaterials of diketopyrrolopyrrole trimer.The synthesized DPP trimer nanomaterial has good photothermal stability,thermal stability and high photothermal conversion efficiency.The nanomaterials of the DPP trimer can produce the photothermal effect with a long wavelength(685 nm)excitation laser to kill cancer cells.