Preparation And Characterization Of Magnetic And Epipolic Composite Nanoparticles Of Multifunctional Hollow Spheres

In recent years, in association with these synthetic endeavors, inorganic multifunctionalnanoparticles that combine optical and magnetic as well as mesoporous/hollowed structures withtailored in an single unit have been receiving great attention, since these materials hold greatpromise for biomedical applications, such as fluorescent labeling, drug delivery carriers andmolecular imaging. In practice, core/shell structure capsules are always chosen as the perfectcandidate to encapsulate the drug. However, still suffer from disadvantages such as low yield,irregular or complicated method, which restrict their application in drug carrier. Considering theabove limitations, we designed a hollow sphere with shell-shell structure, which can overcome theabove disadvantages.1. Uniform Rare-earth Gd2O3hollow spheres with tunable shell thickness have beensuccessfully fabricated in the presence of SiO2as templates via a urea based homogeneousprecipitation method. One can see that the as-obtained Gd2O3hollow spheres consist of uniformmicrospheres with diameters of about580nm. Through varying the times of the precipitationprocedure, the shell thickness can be successfully controlled within the20～55nm range. And thethickness increase of each time of procedure might be~10nm. So we grasped the reasonable timeof ultrasonic treatment for broking the spheres, which can very contribute to controlled releaseapplications.2. Hereafter, we have successfully prepared monodisperse shell/shell nanocompositescomprising magnetic hollow spheres and Gd2O3shells. The synthesis strategy is based on a self-assembly diffusion process. As a form of nanocomposites, the particles combine magneticmaterials and gadolinium oxide to integrate the functions of magnetic and optical responses of theindividual components. In particular, shell/shell nanocomposites of magnetic materials and Gd2O3combine the advantages of individual shells to enhance space utilization of the capsules and greatlyextend the application.3. By doping the Eu3+ions into the Gd2O3host matrix, these nanorattle spheres exhibit brightdown-and upconversion luminescence with red colors under ultraviolet or980nm NIR laserexcitation, which might find potential applications in fields such as drug delivery or biologicallabeling because of their excellent dispersing, magnetism and luminescence properties. Forinstance, the drug carriers are attaching to the surface of cancer cells and the magnetic particles can be directed migration to a specific target, the luminescence and magnetic properties of the carriersare necessary. Generally, the inner magnetic Fe3O4nanoparticles are coated with a SiO2layer. Oneproblem with the structure is that Fe3O4nanoparticles are impossible separated from the liquidphase and re-dispersed for coating. So, we designed a hollow sphere with shell-shell structure,which can overcome the above disadvantages.