Single-crystalline MFe(2)O(4) nanotubes/nanorings synthesized by thermal transformation process for biological applications.
We report a general thermal transformation approach to synthesize single-crystalline magnetic transition metal oxides nanotubes/nanorings including magnetite Fe(3)O(4), maghematite gamma-Fe(2)O(3), and ferrites MFe(2)O(4) (M = Co, Mn, Ni, Cu) using hematite alpha-Fe(2)O(3) nanotubes/nanorings template. While the straightforward reduction or reduction-oxides process was employed to produce Fe(3)O(4) and gamma-Fe(2)O(3), the alpha-Fe(2)O(3)/M(OH)(2) core/shell nanostructure was used as precursor to prepare MFe(2)O(4) nanotubes via MFe(2)O(4-x) (0 < x < 1) intermediate. The transformed ferrites nanocrystals retain the hollow structure and single-crystalline nature of the original templates. However, the crystallographic orientation-relationships of cubic spinel ferrites and trigonal hematite show strong correlation with their morpologies. The hollow-structured MFe(2)O(4) nanocrystals with tunable size, shape, and composition have exhibited unique magnetic properties. Moreover, they have been demonstrated as a highly effective peroxidase mimic catalysts for laboratory immunoassays or as a universal nanocapsules hybridized with luminescent QDs for magnetic separation and optical probe of lung cancer cells, suggesting that these biocompatible magnetic nanotubes/nanorings have great potential in biomedicine and biomagnetic applications.
Fan
Hai-Ming
HM
Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore. msefhm@nus.edu.sg
Yi
Jia-Bao
JB
Yang
Yi
Y
Kho
Kiang-Wei
KW
Tan
Hui-Ru
HR
Shen
Ze-Xiang
ZX
Ding
Jun
J
Sun
Xiao-Wei
XW
Olivo
Malini Carolene
MC
Feng
Yuan-Ping
YP
D032701:Biomimetics; D045744:Cell Line, Tumor; D005290:Ferric Compounds / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D005740:Gases / Q000737:chemistry; D006801:Humans; D008163:Luminescent Measurements; D008175:Lung Neoplasms / Q000473:pathology; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D055620:Optical Phenomena; D010544:Peroxidases / Q000378:metabolism; D013059:Spectrum Analysis, Raman; D013696:Temperature; D028561:Transition Elements / Q000737:chemistry*; D014961:X-Ray Diffraction
D005290:Ferric Compounds; D005740:Gases; D028561:Transition Elements; D010544:Peroxidases