MECHANISM OF BIOLOGICAL FE3O4 SYNTHESIS, IN RELATION TO FERRITE PLATING

The mechanism of the magnetosome (Fe3O4) formations is elucidated from the basic findings on chemical reactions of iron oxides, especially t hose occurring in ferrite plating-a chemical process synthesizing spin el ferrite films from an aqueous solution. It is suggested that in bot h the biomineralization and the ferrite plating, (1) Fe2+-->Fe3+ oxida tion by NaNO2 plays an essential role, (2) gamma-FeOOH is formed as a precursor, and (3) Fe2+ ions are adsorbed on gamma-FeOOH which is foll owed by spinel formation. It is also discussed how to synthesize ferri te films at room temperature by mimicking the biological Fe3O4 formati on.