The role of the collaborative functions of the composite structure of organic and inorganic constituents and their influence on the electrical properties of human bone

Abstract

Background:

The electrical potential, which is generated in bone by collagen displacement, has been well documented. However, the role of mineral crystals in bone piezoelectricity has not yet been elucidated.

Objective:

We examined the mechanism that the composite structure of organic and inorganic constituents and their collaborative functions play an important role in the electrical properties of human bone.

Methods:

The electrical potential and bone structure were evaluated using thermally stimulated depolarized current (TSDC) and micro computed tomography, respectively. After electrical polarization of bone specimens, the stored electrical charge was calculated using TSDC measurements. The CO₃/PO₄ peak ratio was calculated using attenuated total reflection to compare the content of carbonate ion in the bone specimens.

Results:

The TSDC curve contained 3 peaks at 100, 300 and 500°C, which were classified into 4 patterns. The CO₃/PO₄ peak ratio positively correlated with the stored charges at approximately 300°C in the polarized bone. There was a positive correlation between the stored bone charge and the bone mineral density only.

Conclusions:

It is suggested that the peak at 300°C is attributed to carbonate apatite and the total bone mass of human bone, not the three-dimensional structure, affects the stored charge.