Single-Crystalline MFe2O4 Nanotubes/Nanorings Synthesized by Thermal Transformation Process for Biological Applications

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• 作者：Hai-Ming Fan ; Jia-Bao Yi ; Yi Yang ; Kiang-Wei Kho ; Hui-Ru Tan ; Ze-Xiang Shen ; Jun Ding ; Xiao-Wei Sun ; Malini Carolene Olivo ; Yuan-Ping Feng
• 刊名：ACS Nano
• 出版年：2009
• 出版时间：September 22, 2009
• 年：2009
• 卷：3
• 期：9
• 页码：2798-2808
• 年卷期：0
• ISSN：1936-086X

文摘

We report a general thermal transformation approach to synthesize single-crystalline magnetic transition metal oxides nanotubes/nanorings including magnetite Fe₃O₄, maghematite γ-Fe₂O₃, and ferrites MFe₂O₄ (M = Co, Mn, Ni, Cu) using hematite α-Fe₂O₃ nanotubes/nanorings template. While the straightforward reduction or reduction-oxides process was employed to produce Fe₃O₄ and γ-Fe₂O₃, the α-Fe₂O₃/M(OH)₂ core/shell nanostructure was used as precursor to prepare MFe₂O₄ nanotubes via MFe₂O_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 MFe₂O₄ 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.