Change in the Living Functions of Bone Tissue Caused by Carbon Nanotube Reinforcement

The idea of hydroxyapatite (HAp) precipitation on functionalized carbon nanotubes (CNTs) introduces a new aspect of bone tissue engineering. This idea suggests using CNTs as reinforcing scaffolds, to obtain a mechanically enhanced bone tissue, due to the extraordinary mechanical properties of CNTs. However, bone, by its nature, is in direct relation with the applied mechanical loads; and its living functions depend on the mechanical stimuli. Having this in mind, a two-dimensional model of HAp matrix (bone mineral phase) around a CNT inclusion is considered to determine its mechanical response to loading. Two key parameters in conjunction with remodeling process of bone tissue are studied through finite element modeling: stress intensity on a crack tip which may dictate the growth and propagation of the microcracks; and the strain energy distribution in the RVE which is believed to be sensed by some bone cells to control living functions. Results are compared with the case that collagen fiber (CF) exists instead of the CNT inclusion. Modeling shows significant changes in the state of these parameters when material properties of the inclusion are changed. As a result, it can be concluded that replacing CFs in natural bone with CNTs leads to alteration of living functions of bone tissue.