FIG. 1.
Fe-bead characterization. (A and B) SEM (A) and TEM (B) images of Fe-beads, showing the surface structure, 50-nm-diameter pores, and the size of the pores relative to an S. oneidensis MR-1 cell (on the right side in panel B). (C) Schematic diagram providing the dimensions of the bead core and cortex. (D) Percentages of iron in the core of the beads on days 0 and 3 as determined by TEM and EDS, prior to acid extraction. The error bars indicate the standard deviations for 50 EDS measurements from a single experiment (cell density, 6.7 × 108 cell/ml).