title: Wrap-bake-peel process for nanostructural transformation from beta-FeOOH nanorods to biocompatible iron oxide nanocapsules.
abstract: The thermal treatment of nanostructured materials to improve their properties generally results in undesirable aggregation and sintering. Here, we report on a novel wrap-bake-peel process, which involves silica coating, heat treatment and finally the removal of the silica layer, to transform the phases and structures of nanostructured materials while preserving their nanostructural characteristics. We demonstrate, as a proof-of-concept, the fabrication of water-dispersible and biocompatible hollow iron oxide nanocapsules by applying this wrap-bake-peel process to spindle-shaped akagenite (beta-FeOOH) nanoparticles. Depending on the heat treatment conditions, hollow nanocapsules of either haematite or magnetite were produced. The synthesized water-dispersible magnetite nanocapsules were successfully used not only as a drug-delivery vehicle, but also as a T2 magnetic resonance imaging contrast agent. The current process is generally applicable, and was used to transform heterostructured FePt nanoparticles to high-temperature face-centred-tetragonal-phase FePt alloy nanocrystals.
authors.affiliation: National Creative Research Initiative Center for Oxide Nanocrystalline Materials and School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: Yuanzhe
authors.initials: Y
authors.lastname: Piao
authors.forename: Jaeyun
authors.initials: J
authors.lastname: Kim
authors.forename: Hyon Bin
authors.initials: HB
authors.lastname: Na
authors.forename: Dokyoon
authors.initials: D
authors.lastname: Kim
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Baek
authors.forename: Mi Kyeong
authors.initials: MK
authors.lastname: Ko
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Shokouhimehr
authors.forename: Taeghwan
authors.initials: T
authors.lastname: Hyeon
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D049329:Nanostructures / Q000032:analysis* / Q000648:ultrastructure*
chemical_list: D001672:Biocompatible Materials; D005290:Ferric Compounds; C000499:ferric oxide; C021024:ferric hydroxide; D052203:Ferrosoferric Oxide