title: In vitro deposition of hydroxyapatite on cortical bone collagen stimulated by deformation-induced piezoelectricity.
abstract: In the present work, we have studied the effect of the piezoelectricity of elastically deformed cortical bone collagen on surface using a biomimetic approach. The mineralization process induced as a consequence of the piezoelectricity effect was evaluated using scanning electron microscopy (SEM), thermally stimulated depolarization current (TSDC), and differential scanning calorimetry (DSC). SEM micrographs showed that mineralization occurred predominantly over the compressed side of bone collagen, due to the effect of piezoelectricity, when the sample was immersed in the simulated body fluid (SBF) in a cell-free system. The TSDC method was used to examine the complex collagen dielectric response. The dielectric spectra of deformed and undeformed collagen samples with different hydration levels were compared and correlated with the mineralization process followed by SEM. The dielectric measurements showed that the mineralization induced significant changes in the dielectric spectra of the deformed sample. DSC and TSDC results demonstrated a reduction of the collagen glass transition as the mineralization process advanced. The combined use of SEM, TSDC, and DSC showed that, even without osteoblasts present, the piezoelectric dipoles produced by deformed collagen can produce the precipitation of hydroxyapatite by electrochemical means, without a catalytic converter as occurs in classical biomimetic deposition.
authors.affiliation: Departamento de Biología Celular, Universidad Simón Bolívar, Valle de Sartenejas, Aptdo 89000, Caracas 1081-A, Venezuela. knoris@usb.ve
authors.forename: Karem
authors.initials: K
authors.lastname: Noris-Suárez
authors.forename: Joaquin
authors.initials: J
authors.lastname: Lira-Olivares
authors.forename: Ana Marina
authors.initials: AM
authors.lastname: Ferreira
authors.forename: José Luis
authors.initials: JL
authors.lastname: Feijoo
authors.forename: Nery
authors.initials: N
authors.lastname: Suárez
authors.forename: Maria C
authors.initials: MC
authors.lastname: Hernández
authors.forename: Esteban
authors.initials: E
authors.lastname: Barrios
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D032701:Biomimetics; D001842:Bone and Bones / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D003094:Collagen / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D005109:Extracellular Matrix / Q000378:metabolism; D046911:Macromolecular Substances; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000378:metabolism; D011817:Rabbits; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D046911:Macromolecular Substances; D003094:Collagen; D017886:Durapatite