Light Responsive Selenium/Tellurium-containing Polymer For Photopatterning And Cancer Treatment

Light responsive polymers are a kind of functional polymers,that could absorb light energy to induce the physical or chemical change in molecular or intermolecular.As an exogenous stimulus,light has outstanding spatial and temporal controllability.It could induce chemical reaction without contacted with the material at a distance.At the same time,the parameters of light are highly variable,like wavelength,intensity,polarization and so on.These made light responsive polymer become one of the most important research,and have wide applications in self-healing materials,flexible intelligent robots,liquid motion,cancer treatments.The most commonly used photochromisms,such as azobenzenes,spiropyrans,diarylethenes,disulfide bond,are all ultraviolet responsibility.The low transmittance and inducing material aging of UV light are the mainly limited factors for the applications of these photochromisms.Developing new and mild stimulating light responsive polymers could broaden their application areas and be more fit for the actual requirements.The thesis based on selenium/tellurium containing light responsive polymer,detailed studies their applications at material property regulation,3D photo pattern and cancer treatment.The work include three parts as follows:1)Developing wavelength controlled diselenide and disulfide bonds dynamic metathesis,and apply it to tune mechanical properties of polymer materials.Taking advantage of the different bond energies of disulfide bonds and diselenide bonds,they underwent metathesis under UV light to produce Se-S bonds.When irradiated by specific visible light,the Se-S bonds were reversed to the original reactants.The different photostationary state of the reaction were confirmed under different wavelength.Using the wavelength-controlled metathesis,light-triggered bond and cleavage of polymer materials were conducted,and the cleavage process could be induced by laser.Furthermore,the visible light-induced reverse reaction was compatible with reductant catalyzed.The catalytic reductants thermodynamically pushed the exchange forward,while visible light irradiation kinetically pushed it backward.With light as the input energy,the system has a potential for a dissipative system.2)Novel swelling induced 3D photopattern(SPP)were applied on seleniumcontaining thermosetting elastomer.SPP made up for the high demanding for tension device of mechanophotopatterning.This method could be used to pattern on film material,bulk material,cylinder material.The swelling ratio was depended on the degree of the crosslinking and the Young's modulus of the material.The swelling and shrinking of the material were geometric amplification process and narrow process.Compared with light cover mask,the pattern was scaling down.The scaling down size was depended on the swelling ratio of the material.The property of scaling down has a potential to achieve more precision than laser printing.3D pattern was more vivid and showed more details than 2D pattern about the irradiation area.The diselenide bonds made the pattern could be induced by projector equipment directly and made the material could be reprocessing by hot-press method.3)Ultrasensitive ROS responsive and coordinated with various metals system were fabricated on the basis of tellurium containing polymers for triggering the release of the drug and combination of multiple treatments.The coordination effect of tellurium and cisplatinum improved the stability of drugs during the long circulation and restrain the tumor cytotoxicity of these two portions.After a low dose of irradiation,the tumor cytotoxicity could restore.This radiation responsive system possessed less toxicity in non-radiation area and triggered the drug release only by 2 Gy irradiation,which achieved the combination of chemotherapy and radiotherapy.This system has targeting of the radiotherapy and high efficiency of the chemotherapy.Besides,by layer-by-layer method,a light responsive tellurium containing polymer film was fabricated.The tellurium-containing film showed good biocompatibility without light radiation,and showed obvious cell killing activity under the light.Using the light responsiveness of the tellurium-containing polymer,a platform for combination of chemotherapy and photo dynamic therapy was fabricated.