Photocytotoxicity and magnetic relaxivity responses of dual-porous γ-Fe 2O 3@ meso -SiO 2 microspheres

Shou Hu Xuan, Siu Fung Lee, Janet Ting Fong Lau, Xiaoming Zhu, Yi Xiang J. Wang, Feng Wang, Josie M.Y. Lai, Kathy W.Y. Sham, Pui Chi Lo, Jimmy C. Yu, Christopher H.K. Cheng, Ken C F LEUNG*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

46 Citations (Scopus)


Novel high magnetization microspheres with porous γ-Fe 2O 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 2O 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 2O 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 2O 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 2O 3@meso-SiO 2-ZnPC microspheres has been demonstrated for 20 min illumination.

Original languageEnglish
Pages (from-to)2033-2040
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number4
Publication statusPublished - 25 Apr 2012

Scopus Subject Areas

  • Materials Science(all)

User-Defined Keywords

  • drug carrier
  • magnetic resonance imaging
  • nanoparticle
  • photocytotoxicity
  • porosity


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