Preparation Of Superparamagnetic Iron Oxide Nanoparticles And Their Diffusion And Distribution In Rat Brain

In this paper,superparamagnetic iron oxide nanoparticles?SPIONs?modified with different organic compounds were synthesized by high temperature thermal decomposition method by using iron?Fe?acac?₃?as iron source.X-ray diffraction analysis?XRD?and transmission electron microscopy?TEM?were used to analyze the crystal phase and morphology of the samples.Fourier transform infrared spectroscopy?FTIR?was used to analyze the modification of the surface of SPIONs.The nanoparticle size and zeta potential analyzer were used to measure the hydration kinetics particle size and potential value of the samples.the superconducting quantum interferometer device?SQUID?were used to analyze the magnetic properties of the samples.The samples were injected into the brain of SD rats,and the rats were dissected after 24 h to get their brains.The presence and distribution of iron oxide nanoparticles in the brain were observed by inductive coupling plasma emission spectrograph?ICP-OES?and TEM.The main results are as follows:?1?PEG-SPIONs were prepared by high temperature thermal decomposition.The results of characterization showed that the samples had good crystallinity and good dispersibility,an average particle size of 8.8 nm,and PEG was modified on the surface of iron oxide nanoparticles with a hydration kinetics particle size of 22 nm and had good superparamagnetism.The samples were injected into the right ventricle and substantia nigra of rat brains,and the diffusion and distribution of iron oxide nanoparticles were observed by ICP-OES and transmission electron microscopy.It was found that there were more nanoparticles in the cerebellum,hypothalamus and hippocampus of the right ventricle in the rat brains injected with SPIONs into the right ventricle,and the content of SPIONs in other regions was less.The rat brains injected with SPIONs into substantia nigra had a large number of nanoparticles in the midbrain and hypothalamus regions,and ICP-OES showed high iron content in the midbrain region.Both ways found more nanoparticles in the hypothalamus.?2?PEG/PEI-SPIONs were prepared and characterized:The samples had good crystallinity and good dispersibility.The average particle size was 10.3 nm.Both PEG and PEI were modified on the surface of iron oxide nanoparticles with a hydration kinetics particle size of 20 nm,and had good superparamagnetism.The samples were injected into the right ventricle of rat brains,ICP-OES and TEM showed that the nanoparticles was mainly aggregated in the olfactory bulb,thalamus,hypothalamus region and other regions aggregated little.?3?PEG/PVP-SPIONs were prepared and characterized:iron oxide nanoparticles have good crystallinity and good dispersibility,an average particle size of 8.7 nm,and PEG and PVP were modified on the surface of iron oxide nanoparticles with a hydration kinetics particle size water of 20 nm,and had good superparamagnetism.The results of ICP-OES and TEM showed that the nanoparticles were mainly distributed in hippocampus,thalamus and cortex,and other brain regions were less.Comparing the distribution of the above three kinds of nanoparticles,it could be see that all SPIONs are largely distributed in the hypothalamus and hippocampus regions.Closing to the injected points was probably one of the reasons.There was large number of PEG-SPIONs spread to the cerebellum area,suggesting that PEG-SPIONs easily cross the ventricle to reach the cerebellum.PEG/PEI-SPIONs aggregated in the olfactory bulb indicatethat the its ability to spread from the ventricle to the olfactory bulb is relatively strong.PEG-SPIONs were highly aggregated in the midbrain region,indicating that nanoparticles are more difficult to diffuse from the substantia nigra to the surrounding area.In this study,we analyzed and studied the spread and distribution of SPIONs in rat brains,and laid a foundation for future treatment of brain diseases with SPIONs as targeted drug carriers.