TEM images showing the nucleation of HAps
mediated by AS with different
concentrations and mineralization times. (A–C) The mineralization
time was 24 h, but the concentration of AS was set at (A) 0.5, (B)
2, and (C) 8 mg/mL; (D–F) The concentration of AS was fixed
at 2 mg/mL, but the mineralization time was chosen at (D) 2, (E) 6,
and (F) 12 h; (G) HRTEM image showing the nanoneedles of HAps mediated
by AS with the concentration of 2 mg/mL after mineralization for 24
h; and (H) is a high magnification image of (G). White arrows show
the lattice spacings of 0.344 and 0.282 nm, which are corresponding
to the d-spacings of (002) and (211) lattice planes,
respectively.