Ames Lab chemist Tanya Prozorov tried synthesizing crystals, using the proteins with various concentrations of reagents in an aqueous solution, but the particles formed quickly, were small and lacked specific crystal morphology. At the suggestion of Ames Lab senior physicist and crystal growth expert Paul Canfield, the team used polymer gels developed by Mallapragada and Balaji Narasimhan, who are both Ames Lab scientists as well as ISU chemical engineers, to slow down the reaction and help control formation of the nanocrystals and minimize aggregation.
Its simple chemistry, Prozorov said, and you can judge the reaction by the color, watching it go from yellow to green to black as the crystals form. Once the crystals precipitate out, we use a magnet to concentrate the particles at the bottom of the flask, then separate them out to study them further.
Prozorov also conducted electron microscopy analysis of the synthetic nanoparticles which showed that Mms6 produced well-formed, faceted crystals resembling those produced naturally by the bacteria. Powder X-ray diffraction studies verified the crystal structure of the particles.
Ames Lab physicist Ruslan Prozorov, tested the magnetic properties of the synthetic crystals which also showed striking similarities to the bacteria-produced crystals and bulk magnetite. The magnetic studies also showed that the chains of particles formed by the bacteria had a much sharper magnetic transition definition at a higher temperature than single crystals.
Nature found a way to beat the thermodynamics (of crystalline magnetite) by arranging the nanoparticles in such a way that they arent affected by temperature the way individual crystals are, Ruslan Prozorov said.
With this basic understanding of magnetota
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