Discovery of nanocrystalline botanical magnetite

Using TEM and electon diffraction techniques, nanocrystalline magnetite has been found in Fe-rich extracts from disrupted grass cells. Most of the magnetite nanocrystals show cubo-octahedral shapes, but some have hexagonal prism morphologies. Each group has a narrow size distribution typical of intracellular-boundary organized biomineralization processes responsible for bacterial magnetite. The smallest cubo-octahedral botanical nanocrysts (4 + or - 1 nm) are an order of magnitude smaller than their bacterial counterparts. These botanical nanocrystals are self-organized in ordered, mu m-sized agglomerates, distinct from magnetite strings in magnetotactic bacteria and similar to some pedogenic magnetite currently attributed to inorganic processes. The implications of these results on the search for magnetite records of extraterrestrial and ancient terrestrial life, the origin of terrestrial topsoil magnetite and the potential for bioremediation using botanical magnetite are discussed.