Characterization of Fe₃O₄ Magnetosomes by Small-angle X-ray Scattering

Author(s):

Frederick L Beyer, Mark A Allen, and Justin P Jahnke

Abstract:

Small-angle X-ray scattering was used to characterize magnetosome samples as found in M. gryphiswaldense bacteria, after extraction from the bacteria but dispersed in water, and in a powder form after drying. Samples of magnetosomes doped with cobalt were also characterized. The samples all scattered strongly and showed evidence of both form-factor and structure factor scattering. In general, the magnetosomes formed chains of approximately 20 beads when contained in the bacteria. Once removed, the magnetosomes were only chaining in groups of two or three. When dried into a powder, a correlation peak starts to form in the low-q small-angle X-ray scattering data, suggesting aggregation. Finally, it was noted that the cobalt doped magnetite particles tended to be slightly larger in diameter than those for the undoped magnetite.