Highly Orientated Calcification in Newly Formed Bones on Negatively Charged Hydroxyapatite Electrets
Large negative charges induced by electrical polarization on hydroxyapatite (HA) ceramics has been demonstrated to enhance their osteoconductivities. The newly formed bones in the vicinities of the negatively charged surfaces were investigated in the views of crystallography and histology. The newly formed bone layers accompanied by mono-layered osteoblastic cells showed 4 perfect extinction positions in a 360° rotation, parallel and perpendicular to the HA surfaces by the optically polarizing images. The observation revealed that the newly formed bone layers directly bonding to the N-surface were consisted of the well-crystallized and highly orientated HA. Therefore, it was presumed that the enhanced osteobonding by negative surface charges was ascribed to the activation of myeloid cells and the intensified attraction of the HA nuclei by the electrostatic force.
Panjian Li, Kai Zhang and Clifford W. Colwell, Jr.
S. Nakamura et al., "Highly Orientated Calcification in Newly Formed Bones on Negatively Charged Hydroxyapatite Electrets ", Key Engineering Materials, Vols. 284-286, pp. 897-900, 2005