Synthesis And Performance Studies Of Iron-Based Nanocomposites

Nanocatalytic medicine is an interdisciplinary field of catalysis and biology,aiming to utilize the physical or chemical properties of nanomaterials to initiate catalytic reactions in situ in diseased areas,thereby regulating the physiological functions of immune cells or cancer cells,and ultimately treating related diseases（such as cancer）.Iron based nanomaterials are a promising class of nanocatalysts due to their low cost,high catalytic activity,and good biocompatibility.Previous studies have shown that iron based nanomaterials can not only produce reactive oxygen species（ROS）to kill cancer cells,but also regulate immune responses.Compared with single iron based nanomaterials,iron based nanocomposites have richer geometric morphology and chemical composition,and their biological properties are expected to be further improved.Therefore,designing and synthesizing novel iron based nanocomposites with excellent biological properties is of great significance for the development of nanocatalytic medicine.In this thesis,a series of novel iron based nanocomposites have been prepared through morphology（Chapter 2 and Chapter3）and component regulation（Chapter 4 and Chapter 5）,improving their biological properties.The specific research content is as follows:（1）Macrophages play a key role in cancer immunotherapy,so it is important to study the interaction between nanoparticles and macrophages.Iron based nanomaterials have unique advantages in promoting macrophage activation and enhancing cancer treatment effects.However,the effect of morphology regulation of iron based nanomaterials on particle-macrophage interaction has been rarely reported.Therefore,we first propose a sequential growth mechanism of nanorods and nanotubes,and synthesize a triblock structure iron oxide/silica（Fe₂O₃/Si O₂）nanocomposite,providing a new method for morphology regulation of iron based nanomaterials,and this structure is also conducive to enhancing Fenton catalytic activity（Chapter 2）.Based on above work,we propose a multi-tip nanotopology design and synthesize a hexapod Fe₂O₃/Si O₂nanocomposite.By increasing the probability of interaction between the tip of nanomaterials and macrophages,the phagocytic effect is enhanced,providing a new insight into the design of nanomaterials for macrophage-oriented bioapplications（Chapter 3）.（2）Iron based nanomaterials can kill cancer cells through Fenton catalytic reactions.However,the commonly used ferric oxide（Fe₃O₄）nanomaterials in this field have the problems of slow conversion of ferric iron/divalent iron(Fe³⁺/Fe²⁺)and few catalytic active site,and their catalytic activity in cancer cells still needs to be improved.To solve this problem,we propose a Fe²⁺doping strategy.By doping Fe²⁺into two-dimensional hydrogenated titanium dioxide(Ti O_2-x)nanosheets,we realize the synergistic catalysis of Fe²⁺and Ti³⁺,and enhance their generation of hydroxyl radical（·OH）and toxic effects on cancer cells,providing a new idea for the design of iron ion doped nanomaterials（Chapter 4）.In addition,an impregnation-gas phase reduction method is developed to uniformly load gold particles into an iron based metal organic framework（Fe-MOF）,enhancing the cascade catalytic reaction of gold and iron species.This work not only improves toxic effects of iron based nanomaterials on cancer cells,but also proposes a new method for preparing metal organic framework@gold nanocomposites（Chapter 5）.