Researchers mimic bacteria to produce magnetic nan...( When it comes to designing something...)

When it comes to designing something, its hard to find a better source of inspiration than Mother Nature. Using that principle, a diverse, interdisciplinary group of researchers at the U.S. Department of Energys Ames Laboratory is mimicking bacteria to synthesize magnetic nanoparticles that could be used for drug targeting and delivery, in magnetic inks and high-density memory devices, or as magnetic seals in motors.

Commercial room-temperature synthesis of ferromagnetic nanoparticles is difficult because the particles form rapidly, resulting in agglomerated clusters of particles with less than ideal crystalline and magnetic properties. Size also matters. As particles get smaller, their magnetic properties, particularly with regard to temperature, also diminish.

However, several strains of bacteria produce magnetite (Fe3O4) fine, uniform nanoparticles that have desirable magnetic properties. These magnetotactic bacteria use a protein to form crystalline particles about 50 nanometers in size. These crystals are bound by membranes to form chains of particles which the bacteria use like a compass needle to orient themselves with the Earths magnetic field.

To see if researchers could learn from the bacteria, Surya Mallapragada, Ames Laboratory Materials Chemistry and Biomolecular Materials program director pulled together a team that included microbiologists, biochemists, material chemists, chemical engineers, materials scientists and physicists from Ames Laboratory and Iowa State University.

As a starting point, former ISU microbiologist Dennis Bazylinski, now at the University of Nevada-Las Vegas, isolated several strains of magnetotactic bacteria for use in the study.

Based on earlier work by a Japanese research team, Ames Laboratory biochemist Marit Nilsen-Hamilton looked at several proteins known to bind iron, including Mms6 found in magnetotactic bacteria, which she cloned from the bacteria. This protein is
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