No 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.

No abstract

Bone healing and growth are controlled by the rate of deposition of hidroxiapatite (HA). This process have been so far accredited to the work of osteoblasts, which are attracted by the electrical dipoles produced either by piezoelectricity, due to deformation of the bone, specially the collagen in it, or due to outside electrical stimuli. The present work shows that even without osteoblasts present, the piezoelectric dipoles produced by deformed collagen, can produce the precipitation of HA by electrochemical means, without catalyzer as in biomimetic deposition. These findings could clarify the contribution of osteoblasts in bone growth as compared to the electrochemical action by itself. Further studies ascertaining the osteoblastic activity due to the electric field are being advanced.

No abstract