Fig. 4: Type I collagen fibril mineralized with γ-FeOOH in the presence of pAsp.

a TEM image of a collagen fibril containing γ-FeOOH platelets. b LDSAED of a showing wide arcs of γ-FeOOH (002) diffraction along the collagen fibril axis. The pattern is obtained after radial alignment and averaging of 9 individual patterns (see Supplementary Figs. 13 and 14, and Supplementary Table 1). The direction of the collagen fibril long axis is highlighted by the white arrow. c, d Tomographic reconstruction y- and z-slices, respectively. d Is averaged from 10 adjacent slices to enhance the contrast. The orientations of some γ-FeOOH platelets are highlighted by yellow arrows in c, d. e, f Longitudinal and lateral angular distribution (α and γ, as indicated in c and d) of the platelets, respectively. ~150 crystals were measured that were at least 10 nm apart for e and 50 nm apart for f. Scale bars: a 100 nm, b 2 nm⁻¹, c, d 50 nm.