Scientists at the University of Manchester have found a clean and green way of making tiny magnets for high tech gadgets – using natural bacteria that have been around for millions of years.
Image credit: University of Manchester
The work by a team of geomicrobiologists from the University of Manchester paves the way for nanometer-size magnets – used in mobile phones and recording devices – to be made without the usual nasty chemicals and energy intensive methods.
Researchers studied iron-reducing bacteria that occur naturally in soils and sediments and found they can be used to create iron oxide nanoparticles with magnetic properties similar to those created through complex chemical processes.
Working with colleagues in Birmingham and Cardiff, the Manchester researchers also found a way of exercising precise control over the size and magnetic strength of nanomagnets produced.
The high-tech particle accelerators at the Advanced Light Source at the famous Berkeley Labs near San Francisco, and the UK’s Diamond Light Source in Oxford at Harwell were used to verify findings.
Researchers added cobalt, manganese or nickel to the basic iron-based energy source used by bacteria, which resulted in the production of tiny magnets containing these elements. This greatly enhanced their useful magnetic properties.
Aside from being used in the latest gadgets, nanomagnets also have the potential to be used in drug delivery systems and cancer therapies to carefully focus and target the release of chemicals into the body.
Metal-reducing bacteria live in environments deficient in oxygen and react with oxidised metals to produce natural magnets in the ground beneath our feet.
And now the research team has developed a way of harnessing pure strains of these bacteria – which are in plentiful supply and reproduce quickly – to produce large quantities of nanomagnets at an ambient temperature.
This compares favorably to the extreme temperatures – as high as 1000 degrees Celsius – needed to create nanomagnets using current methods.
Prof Richard Patrick, Professor of Earth Science, said: “This is exciting work that raises the exciting prospect of a biologically friendly, energy-efficient method of producing nanomagnets tailored for different uses.”
A paper – ‘Harnessing the extracellular bacterial production of nanoscale cobalt ferrite with exploitable magnetic properties’ – outlining the research was published recently in the journal ACS Nano.
The research was supported by grants from the Engineering and Physical Sciences Research Council (EPSRC) and the Biotechnology and Biological Sciences Research Council (BBSRC).
More information about the work: http://www.als.lbl.gov/als/science/sci_archive/193nanomagnets.html
Full citation for the journal paper is: V.S. Coker, N.D. Telling, G. van der Laan, R.A.D. Pattrick, C.I. Pearce, E. Arenholz, F. Tuna, R. Winpenny, and J.R. Lloyd, "Harnessing the extracellular bacterial production of nanoscale cobalt ferrite with exploitable magnetic properties,"ACS Nano 3, 1922 (2009)
Members of the research team are available for comment. Images are also available. Please contact Alex Waddington, Media Relations Officer, Tel 0161 275 8387 / 07717 881569.
The Advanced Light Source (ALS) is a national user facility in the United States that generates intense light for scientific and technological research. As one of the world's brightest sources of ultraviolet and soft x-ray beams - and the world's first third-generation synchrotron light source in its energy range - the ALS makes previously impossible studies possible. The facility welcomes researchers from universities, industries, and government laboratories around the world. It is funded by the U.S. Department of Energy's Office of Basic Energy Sciences