Letter abstract
Nature Nanotechnology 3, 158 - 162 (2008)
Published online: 2 March 2008 | doi:10.1038/nnano.2008.35
Subject Categories: Nanobiotechnology | Nanomagnetism and spintronics | Synthesis and processing
Controlled cobalt doping of magnetosomes in vivo
Sarah Staniland1, Wyn Williams2, Neil Telling3, Gerrit Van Der Laan3,4, Andrew Harrison5,6 & Bruce Ward1
Abstract
Magnetotactic bacteria biomineralize iron into magnetite (Fe3O4) nanoparticles that are surrounded by lipid vesicles. These 'magnetosomes' have considerable potential for use in bio- and nanotechnological applications because of their narrow size and shape distribution and inherent biocompatibility1, 2, 3. The ability to tailor the magnetic properties of magnetosomes by chemical doping would greatly expand these applications4, 5; however, the controlled doping of magnetosomes has so far not been achieved. Here, we report controlled in vivo cobalt doping of magnetosomes in three strains of the bacterium Magnetospirillum. The presence of cobalt increases the coercive field of the magnetosomes—that is, the field necessary to reverse their magnetization—by 36–45%, depending on the strain and the cobalt content. With elemental analysis, X-ray absorption and magnetic circular dichroism, we estimate the cobalt content to be between 0.2 and 1.4%. These findings provide an important advance in designing biologically synthesized nanoparticles with useful highly tuned magnetic properties.
- School of Biological Sciences, University of Edinburgh, Kings Buildings, Edinburgh, UK
- School of Geosciences, University of Edinburgh, Kings Buildings, Edinburgh, UK
- Magnetic Spectroscopy Group, Synchrotron Radiation Department, Daresbury Laboratory, Warrington, UK
- Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE, UK
- School of Chemistry, University of Edinburgh, Kings Buildings, Edinburgh, UK
- The Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble, Cedex 9, France
Correspondence to: Sarah Staniland1 e-mail: s.s.staniland@ed.ac.uk
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