| Composite nanoparticles, especially functional composite nanoparticles have been broadly researched in recent period. Magnetic composite nanoparticles, which are combined magnetic materials (e.g., FeaO4, y-Fe2O3and oxide of Ni, CO and Mn) with kinds of functional polymer materials (e.g., environmental sensitivity polymer, fluorescent polymer and targeted drug polymer), can be widely used in the field of bio-pharmaceutical (e.g., targeted drug delivery, drug sustained-release, protein delivery) and industrial application (e.g., water purification). In conclusion, magnetic nanocomposites represent great potential for further research,In this paper, the nanoparticles with the difunctional of fluorescent and magnetic and trifunctional of magnetic, fluorescence and X-ray tomography(CT) contrast imaging have been synthesised by methods of ligand exchange and soap-free emulsion polymerization. Ligand exchange method is took by using the new synthetic ligands replace the original ligand on material surface under some conditions, and it’s convenient for the acquisition of water-based Fe3O4 nanoparticles. Soap-free emulsion polymerization have distinct advantages in preparing biomedical microspheres because of mild reaction and absent emulsifier. The specific process is as follows:After utilizing coprecipitation method and subsequent modification with oleic acid, oil-based Fe3O4 magnetic nanoparticles with a narrow size distribution are obtained. And a kind of amphiphilic polymer containing rare earth are synthesized by using poly(ethylene glycol) methacrylate, methacryloxy propyl trimethoxyl silane and a complex Eu(AA)3Phen as monomers. The oil-based Fe3O4 nanoparticles are then used as magnetic center, modified with the amphiphilic polymer via ligand exchange reaction to prepare water-based magnetic fluorescent particles (PMNPs). The morphological structure, magnetic and fluorescent properties of the PMNPs are characterized by different testing instruments. Results show that the amphiphilic polymer is coated onto the surface of Fe3O4 nanoparticles effectively and evenly. The PMNPs have a good dispersibility in aqueous phase and can keep a uniform particle size. Average particles diameter of the particles is just around 45 nm. The particles also have a saturation magnetization of 2.3 emu/g at room temperature, and the rare earth Eu3+ in these PMNPs have obvious characteristic emission spectra at 594 nm and 619 nm with a excitation spectra at 327 nm.A new functional europium(Ⅲ) complex containing iodine has been developed in this article. Then the functional nanocomposite combine the complex and Fe3O4 nanoparticle has been prepared by seed emulsifier-free polymerization. The new complex exhibits excellent characteristic of X-ray imaging and fluorescence, and shows a better contrast effect in smaller iodine payload than iodine in composition. The nanocomposite combining complex’s double function with superparamagnetism can be used for computed X-ray tomography (CT), magnetic resonance imaging (MRI) and optical contrast image, and reflect many valuable properties:It has a good uniform dispersion and high encapsulation rate. In vitro CT, it still has obvious contrast effect with a low iodine payload below 4.8 mgl/ml. The paramagnetic properties of nanocomposite are serviceable which maximum saturation magnetization is 2.16 emu/g and transverse relaxivity rate is 259.59 mM-1 S-1. In vivo optical imaging, it exhibit vivid fluorescence dots under 2-photon confocal scanning laser microscopy (CLSM) in liver and spleen. Meanwhile, the synthesis of complex and nanocomposite also suggest a new way of using iodinated contrast agents. |
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