ABSTRACT
Extracellular matrix (ECM) of bone tissue is a typical composite system consisting of a mineral phase (hydroxyapatite [HA]—more precisely bone mineral is a hydroxyl-and calcium-decient, carbonated apatite) and an organic phase (collagen and noncollagenous proteins such as osteocalcin, osteonectin, bone sialoprotein) (Boskey 2005). This composite ECM structure can be described in terms of hierarchical levels of organization from nanometers, through micrometers, and nally to millimeters scale range (Rho et al. 1998).
