Photocytotoxicity and magnetic relaxivity responses of dual-porous γ-Fe2O3@meso-SiO2 microspheres

ACS Appl Mater Interfaces. 2012 Apr;4(4):2033-40. doi: 10.1021/am300008x. Epub 2012 Mar 21.

Abstract

Novel high magnetization microspheres with porous γ-Fe(2)O(3) core and porous SiO(2) shell were synthesized using a templating method, whereas the size of the magnetic core and the thickness of the porous shell can be controlled by tuning the experimental parameters. By way of an example, as-prepared γ-Fe(2)O(3)@meso-SiO(2) microspheres (170 nm) display excellent water-dispersity and show photonic characteristics under externally applied a magnetic field. The magnetic property of the γ-Fe(2)O(3) porous core enables the microspheres to be used as a contrast agent in magnetic resonance imaging with a high r(2) (76.5 s(-1) mM(-1) Fe) relaxivity. The biocompatible composites possess a large BET surface area (222.3 m(2)/g), demonstrating that they can be used as a bifunctional agent for both MRI and drug carrier. Because of the high substrate loading of the magnetic, dual-porous materials, only a low dosage of the substrate will be acquired for potential practical applications. Hydrophobic zinc(II) phthalocyanine (ZnPC) photosensitizing molecules have been encapsulated into the dual-porous microspheres to form γ-Fe(2)O(3)@meso-SiO(2)-ZnPC microspheres. Biosafety, cellular uptake in HT29 cells, and in vitro MRI of these nanoparticles have been demonstrated. Photocytotoxicity (λ > 610 nm) of the HT29 cells uptaken with γ-Fe(2)O(3)@meso-SiO(2)-ZnPC microspheres has been demonstrated for 20 min illumination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Survival / drug effects
  • Drug Carriers / chemistry
  • Drug Delivery Systems / instrumentation
  • Ferric Compounds / chemistry*
  • HT29 Cells
  • Humans
  • Magnetic Resonance Imaging / instrumentation
  • Magnetics
  • Microspheres
  • Nanoparticles / chemistry
  • Nanoparticles / toxicity*
  • Porosity
  • Silicon Dioxide / chemistry*

Substances

  • Drug Carriers
  • Ferric Compounds
  • ferric oxide
  • Silicon Dioxide