Fracture Resistance and Strain Energy Status in Bone Tissue Grown on Carbon Nanotube Scaffold instead of Collagen Fiber

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. By nature, however, bone is in direct relation with the applied mechanical loads, and its living functions depend on the mechanical stimuli. With this in mind, a two-dimensional model of HAp matrix (bone mineral phase) around a CNT inclusion is considered todetermine its mechanical response to loading. Two key parameters are studied through finite element modeling in conjunction with remodelling process of bone tissue: stress intensity on a crack tip, which may dictate the growth and propagation of the microcracks; and strain energy distribution in the representative volume element (RVE), which is believed to be sensed by some bone cells that control living functions. Results are compared with natural bone, i.e., with collagen fiber (CF) inclusions replacing the CNT inclusions. Modeling shows significant changes in the state of these parameters when the 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.

Keywords:

Bone tissue engineering , carbon nanotube , crack propagation