Fabrication And Properties Of Multifunctional Fluorescent-magnetic Yolk-shell Hybrid Nanostructures

Yolk-shell nanocapsules (NCs) are a special class of core-shell nanostructures with unique properties of moveable cores, interstitial hollow spaces between the movable core and shell sections, and the functional shells, which have attracted much attention due to their unique properties and potential applications in the fields of catalysis and nanomedicine.The selected-control preparation of uniform core-shell and yolk-shell architectures combining the multiple functions of superparamagnetic iron oxide (SPIO) core and europium-doped yttrium oxide (Y2O3:Eu) shell in a single material with tunable fluorescent and magnetic properties has been successfully achieved by simple modified sol-gel method and controlling heat treatment conditions. Furthermore, the shell thickness and interior cavity of SPIO@Y2O3:Eu core-shell and yolk-shell nanostructures can be precisely tuned. Importantly, the as-prepared SPIO@Y2O3:Eu yolk-shell nanocapsules (NCs) modified with amino groups as cancer cell fluorescent imaging agents are also demonstrated. To the best of our knowledge, this is the first report on the selected-control fabrication of uniform SPIO@Y2O3:Eu core-shell nanoparticles (NPs) and yolk-shell NCs. The combined magnetic manipulation and optical monitoring of magnetic-fluorescent SPIO@Y2O3:Eu yolk-shell NCs will open up many exciting opportunities in dual imaging for targeted delivery and thermal therapy. Additionally, the preparation of core-shell architectures combining the multiple functions of upconversion fluorescence properties of lanthanide ions codoped fluorine yttrium sodium (NaYF4:Yb3+, Er3+, Gd3+) core and HP-doped mesoporous SiO2(mSiO2) shell has been successfully achieved by a similar approach as described above. Subsequently, The PEI deposited on the surface of the core-shell NPs and thus formed a protective layer, which could prevent the dissolution of the near the outer surface of the core-shell NPs by heat-treatment, and finally the formation of the yolk-shell structure of nanocapsules. The as-prepared nanocapsules have potential applications in fluorescence imaging, biological detection, magnetic resonance imaging and photodynamic therapy.