Structure,Catalytic Performance Of Platinum-based Nanoparticles And Their Application In Radiation Protection

In the 21st century,nuclear technology has rapidly developed and gradually applied to all walks of life that involve human daily life.However,we must also be aware of the harm that ionizing radiation can cause to our bodies.H₂O molecules and O atoms that are abundantly present in the living body undergo high-energy ionizing radiation and are cleaved to generate large amounts of reactive oxygen species?ROS?,including oxygen radicals(O^2-),hydroxyl radicals?�OH?,and Hydrogen peroxide?H₂O₂?,which will cause the entire organism to suffer severe oxidative damage.In fact,as the intermediate product of the oxygen reduction reaction,active oxygen species can be catalytically reduced to H₂O by efficient catalytic material,and the function of the organism can be recovered.With the development of nanotechnology,nanomaterials have good catalytic performance and can effectively reduce ROS.At the same time,the nanoparticle size and surface chemistry are easily regulated,effectively prolong blood half-life and enhance intracellular uptake.Therefore,nanomaterials are widely used in the biomedical field.After comprehensive analysis,this paper studied the radiation protection of ultrasmall Pt clusters and conducted a series of in vitro and in vivo radiation protection experiments.The main experiment content and results are:?1?In this paper,platinum-based nanoparticles with a variety of surface morphologies were successfully prepared using a variety of synthetic methods.Firstly,ultrasmall Pt clusters were prepared by liquid-phase reduction method.Then platinum-based nanocrystalline materials including ultrasmall Pt Clusters,PtPd hollow nanocubes and PtPdRh hollow nanocubes were successfully prepared by solvothermal synthesis.Finally,PtPd alloy concave nanocubes were successfully prepared.In this paper,physical properties such as size and surface morphology of Pt nanoparticles were analyzed by means of transmission electron microscopy,UV-Vis absorption,X-ray diffraction,and other physical characterizations;the ability of platinum-based nanoparticles catalyzing the reduction of H₂O₂ was studied by electrochemical test and ABTS test.The results show that PtPdRh hollow nanocube has the best catalytic performance and the size is also relatively small.ultrasmall Pt Clusters have small size,strong stability and good water solubility.?2?The in vitro radiation protection effect of ultrasmall Pt clusters was studied.The radiation protection performance of ultrasmall Pt clusters was detected by cell survival experiment,the change of biological indicators of radiation induced ROS level and nuclear DNA content.In vitro experiments showed that the ultrasmall Pt clusters have low cytotoxicity and strong radiation protection effect.?3?The in vivo radiation protection effect of ultrasmall Pt clusters was studied.The 30-day survival rate experiment has shown that the survival rate of irradiated mice can be effectively increased to 30%.The collection and analysis of superoxide dismutase?SOD?and malondialdehyde?MDA?levels in mice before and after irradiation revealed that ultrasmall Pt clusters can significantly reduce ROS level,effectively increase the level of SOD activity,and significantly reduce the production of MDA.The assessment of fetal nucleus?BMNC?and DNA quantity demonstrated that ultrasmall Pt clusters can effectively protect and repair the hematopoietic system.?4?The toxicity of ultrasmall Pt clusters was systematically studied.It was studied through analysis the accumulated urinary excretion,blood drug concentration,and biochemical blood routine.The results show that 80%of the administered dose could be excreted through the kidney,showing a high renal clearance rate.Longer blood half-life?1 h?,while no significant effect on the blood system and various organs,indicating that ultrasmall Pt clusters have low biological toxicity.