Ferrihydrite Fundamentals
ARC Discovery Grant 2003-2006
Through collaboration with A/Prof. Tim St Pierre (UWA) and A/Prof Craig Buckley (Curtin App. Physics), researchers at the NRI are involved in an ARC Discovery project investigating the structure and chemistry of ferrihydrite – a poorly crystalline iron oxyhydroxide. The overarching goal of this project is to obtain the depth of knowledge necessary to achieve specific size, composition and morphology control in the crystallization of nanometer-sized iron oxides.
Excess iron in the body is stored in the form of ferrihydrite within the protein ferritin. Ferritin consists of an outer protein shell 12 nm in diameter. Inside this shell an iron-containing core forms in an inner spherical space of roughly 8 nm diameter
The degree of crystallinity of the ferrihydrite particles within ferritins can vary from relatively well-ordered ferrihydrite through to a non-crystalline state as determined by electron diffraction measurements. The degree of crystallinity and particle size distribution of the inorganic particles in a native ferritin depend on the source of the ferritin and have also been observed to vary with pathological condition.
The project focuses on the structural characteristics of ferrihydrite, which is a key intermediate in the formation of other iron oxides. The project will employ characterization techniques such as small-angle scattering, high resolution TEM, electron nanodiffraction and magnetic energy barrier distribution measurements to study crystallization processes of ferrihydrite, both in vivo and in vitro. The knowledge gained from the biological realm will allow us to devise new laboratory techniques for the preparation of nanoparticles, and provide important information about iron biomineralization to advance the treatment of iron overload diseases.
TEM image of ferrihydrite particles in the liver of an iron-overloaded rat.
TEM image of the iron-oxyhydroxide phase known as schwertmannite showing a morphology comprised of radiating whiskers.
High resolution image of a schwertmannite whisker showing individual oriented ferrihydrite crystallites.