Preparation And Study Relaxivity Of Superparamagnetic Nanoparticles Clusters

Magnetic nanomaterials were widely studied and applied in various technical fields due to the properties of nanomaterials and magnetic properties. They have become important tools for the diagnosis, treatment, specific pathogens and separate biological species. Magnetic nanomaterials have unique properties to provide a new platform and opportunities for biomedical applications, shch as medical imaging, immunoassay, drug delivery. Therefore, the study of magnetic nanocompos ites has important significance. In this paper we made a series of studies of magnetic nanomaterials,such as Preparation, structure, morphology, magnetic properties and relaxivity. The main contents and innovations are as follows: 1. Preparation and characterization of iron oxide nanomaterialsWe used the thermal decomposition of iron oleate prepared out of Fe3O4 nanoparticles, explored the impacts of the amount of oleyl alcohol and the reflux temperature to the particle size of Fe3O4 nanoparticles. Samples were characterized by XRD, laser particle size analyzer, magnetometer, etc. The results showed that with increasing the amount of oleyl alcohol and reducing the reflux temperature, the particle size smal er of Fe3O4 nanoparticles. 2. Preparation and Characterization of Superparamagnetic Nanoparticles Clusters(1) Graphene oxide functionalized superparamagnetic nanoparticle clusters were prepared in this paper. The samples were characterized by XRD、TEM、FT-IR、VSM and TG, etc. The results showed that the graphene oxide functionalized superparamagnetic nanoparticle clusters has a good water-soluble and superparamagnetic. The composite materials were further modified of polyethylene glycols that have good dispersibility and stability in PBS buffer solution(2) Use of DHC A as intermediates for preparing a PEI functionalized iron oxide nanocomposite.samples were characterized by FT-IR and Zeta. The results showed this method is simple, mild reaction conditions, the preparation time is short, Polyethyleneimine functional iron oxide nano-composite material has good dispersion and stability in water and PBS solution.(3) Fe3O4 nanoparticles were modified with polyethylene glycol monomethyl ether by thiol-click chemistry method. They were characterized by XRD, TEM, FT-IR, Raman, TG, VSM and UV. It was showed that this method was simple, the reaction conditions was mild and the operating conditions was easy. These functionalized Fe3O4 nanoparticles were not only well dispersed in water and PBS, but also showed superparamagnetic property. 3. ResearchIn this paper, the relaxation behavior of dopamine function of iron oxide nanocomposites and graphene oxide- modified iron oxide nanoparticles were characterized, that with increasing concentration of iron ions, longitudinal relaxation time is reduced. Dopamine functionalized magnetic iron oxide nano-particles in aqueous solution at 10 m T value R1 is 0.65 m MS-1, The time domain signal of water is growth with increasing polarization time at a certain time in 10 m T and the value of countdown which is spin- lattice relaxation time is 3.05 S-1. Larger diameter graphene oxide functionalized magnetic nanoparticles clusters r1 and r2 values bigger than the smal er diameter...