TEM images of calcium phosphate minerals and related SAED patterns. High magnification TEM images of the control (a), OSC (b), and OSN (c) after 120 min of incubation are presented. The formation of HA crystals is clear in the presence of OSN. Arrows show the projection of HA crystals aligned perpendicular (white) and parallel (black) to the substrate. SAED patterns of the particles formed in the presence of OSC and control show the amorphous structure, whereas in the presence of OSN, single crystal diffraction patterns are indexed as the HA (002), (211), and (004) crystallographic planes.