title: Photocytotoxicity and magnetic relaxivity responses of dual-porous γ-Fe2O3@meso-SiO2 microspheres.
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.
authors.affiliation: Institute of Molecular Functional Materials and Department of Chemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.
authors.forename: Shou-hu
authors.initials: SH
authors.lastname: Xuan
authors.forename: Siu-Fung
authors.initials: SF
authors.lastname: Lee
authors.forename: Janet Ting-Fong
authors.initials: JT
authors.lastname: Lau
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhu
authors.forename: Yi-Xiang J
authors.initials: YX
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Josie M Y
authors.initials: JM
authors.lastname: Lai
authors.forename: Kathy W Y
authors.initials: KW
authors.lastname: Sham
authors.forename: Pui-Chi
authors.initials: PC
authors.lastname: Lo
authors.forename: Jimmy C
authors.initials: JC
authors.lastname: Yu
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
authors.forename: Ken Cham-Fai
authors.initials: KC
authors.lastname: Leung
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems / Q000295:instrumentation; D005290:Ferric Compounds / Q000737:chemistry*; D019073:HT29 Cells; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D008280:Magnetics; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D005290:Ferric Compounds; C000499:ferric oxide; D012822:Silicon Dioxide