Fig. 5

Visualization of osteoblasts and collagen fibers (bone) during the bone induction process. At an early stage of bone induction, the morphology of osteoblasts shows spindle shape and collagen fibers are arranged in a specific (anisotropic) direction (upper panels). As the bone matures, the appearance of collagen fibers becomes isotropic. The osteoblasts spread across the surface of the induced bone, and the morphology of osteoblasts changes into a round or cuboidal shape [15]. Cyan, osteoblasts expressing Col2.3-ECFP; blue, bone tissues (second harmonic generation, SHG). Scale bar, 20 μm