This is the peer reviewed version of the following article: Vazquez Sancho, F., Abdollahi, A., Damjanovic, D., Catalan, G. Flexoelectricity in bones. "Advanced materials", 18 Gener 2018, vol. 30, núm. 9, p. 1705316-1-1705316-14, which has been published in final form at DOI: 10.1002/adma.201705316. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

ones generate electricity under pressure, and this electromechanical behavior is thought to be essential for bone's self-repair and remodeling properties. The origin of this response is attributed to the piezoelectricity of collagen, which is the main structural protein of bones. In theory, however, any material can also generate voltages in response to strain gradients, thanks to the property known as flexoelectricity. In this work, the flexoelectricity of bone and pure bone mineral (hydroxyapatite) are measured and found to be of the same order of magnitude; the quantitative similarity suggests that hydroxyapatite flexoelectricity is the main source of bending-induced polarization in cortical bone. In addition, the measured flexoelectric coefficients are used to calculate the (flexo)electric fields generated by cracks in bone mineral. The results indicate that crack-generated flexoelectricity is theoretically large enough to induce osteocyte apoptosis and thus initiate the crack-healing process, suggesting a central role of flexoelectricity in bone repair and remodeling.

Peer Reviewed