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

Article type: Research Article

Authors: Kohata, Kazuhiro^a | Itoh, Soichiro^a | Horiuchi, Naohiro^a | Yoshioka, Taro^b | Yamashita, Kimihiro^{a; *}

Affiliations: [a] Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan | [b] Department of Orthopedic Surgery, Kawakita General Hospital, 1-7-3 Asagaya-kita, Suginami-ku, Tokyo 166-8588, Japan

Correspondence: [*] Corresponding author: Kimihiro Yamashita, Department of Inorganic Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan. Tel.: +81-3-5280-8016; Fax: +81-3-5280-8125; E-mail: [email protected].

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.

Keywords: Electrical property, human bone, electrical polarization, carbonate apatite, bone mineral density

DOI: 10.3233/BME-161587

Journal: Bio-Medical Materials and Engineering, vol. 27, no. 2-3, pp. 305-314, 2016