Preparation Of Light-Responsive Carbon-based Nanozymes And Regulation Of Anti-Oxidation/Pro-Oxidation Ability

The disorder of the redox state of the biological system caused by oxidative stress can cause a variety of clinical dysfunctions and diseases.Therefore,controlling the balance of oxidation and reduction is the key to maintaining the health of the body,and it is also the difficulty of current research.Traditional antioxidants and pro-oxidants can only adjust the redox level in one direction.Nanoenzyme materials with oxidoreductase-like activity exhibit antioxidant and pro-oxidant activities that can be adjusted with the environment,providing a new idea for breaking through this bottleneck.In this paper,around the theme of reversible regulation of the anti-oxidation/pro-oxidation activity of nanoenzymes,two carbon-based nanocomposites were constructed,and researches on scavenging free radicals and light-triggered generation of ROS under no light were carried out,and the anti-oxidation/pro-oxidation ability was achieved.Controllable regulation reveals the regulation mechanism,and explores the application possibilities of such nanoenzymes in biological monitoring and biological protection.(1)The adjustment of the redox ability of the light-responsive nitrogen-doped carbon and metal organic framework composite material:The light-responsive UIO-66 loaded NCDs nanocomposite material(NC/UiO)was designed and prepared by the hydrothermal method and simple physical mixing method.The experimental results show that UiO-66,which does not have enzyme-like activity,is compounded with NCDs,and it has both anti-oxidation in the dark and light-triggered pro-oxidation ability,showing oxidase-like activity,and different loadings of NC/UiO can promote oxidation./The anti-oxidant law is the same.The electron spin resonance spectrometer also confirmed the generation of ROS(hydroxyl radicals,superoxide radicals and singlet oxygen)under light,and discussed the mechanism of light-triggered generation of ROS.In addition,we used the simulated oxidase activity and photoluminescence properties of NC/UiO materials to detect the biomolecules glutathione and Fe³⁺.(2)Light induced the redox ability conversion of N-doped carbon coated Aunanostructures:we use hydrothermal method and water bath method,design and prepare a visible light responsive gold-carbon composite nanocomposite material(Au/NC)by combing Auand N-doped carbon nanostructure(Au/NC).It is found that Au/NC can efficiently scavenge reactive oxygen species(ROS)and free radicals,showing intrinsic antioxidant activity.Upon the irradiation with visible light,we observe that Au/NC can generate ROS(e.g.hydroxyl radical,superoxide and singlet oxygen)and exhibit efficient oxidase-like activity to accelerate the oxidation of TMB,showing pro-oxidant capability.The light activated oxidative activity was ascribed into the synergistic effects of photo-excitation of NC and the surface plasmon resonance of Aunanoparticles.In addition,we demonstrate the application of anti-and pro-oxidant capability of Au/NC in inhibition or acceleration of oxidation of Monascus pigments and Fe²⁺,which is switched by incident light.In summary,these nanocomposite materials exhibited controllable anti-oxidation and oxidation-promoting ability,and they have been applied in biology.These results will be of significant interest in modulating the biological redox condition for responsive and precise nanomedicine.