Electromechanical Behavior Of Bone Tissue And Numerical Analysis For Osteoblast In Vitro

Bone will produce electrical potential when subjected to deformation. It is necessary to research the role of the potential in bone growth, remodeling. According to the physiological structure of bone tissue, the biphasic porous medium model, which is based on the mixture theory in continuum frame, is established to depict the distortion and stress field of bone matrix, the flowing field and the resulting electric field when the bone tissue is subjected to outside force. In order to investigate the growth law of bone tissues deeply, osteoblast(the seeded cell of bone tissue engineering) is regarded as a incompressible viscoelastic medium. Then the mechanical behavior of oeteoblast was analyzed, which is the basis to culture bone tissue.The paper consider bone tissue as an biphasic porous medium, which is composed of solid bone matrix and liquids as extracellular fluid. On the other hand, bone tissue can produce electric potential when it is subjected to outside force. So dynamic governing equations can be established through combining the biphasic porous medium model and the streaming potential model, which describe the coupling between the distortion and fluid flow as well as the streaming potential. Then the penalty finite element formula can be derived through Galerkin weighted residual method. To test the model, the paper calculate a cantilever sample and a four point bending beam under near static load and sinusoidal load. The result shows that the potential difference between the upper side and bottom side of the cantilever sample present the biphasic pulse when it is under step load, the result also shows the potential between the upper side and bottom side of the four point bending beam adds with the frequency of load, but the phase difference changes opposite from the potential. These results are consistent with the results from Gross and Salzstein and so on.Osteoblast is the seeded cell of bone tissue engineering. Now, in order to research the response of the osteoblast when it is cultured with mechanical stimulating, the paper consider the osteoblast as an homogeneous, isotropic, incompressible viscoelastic medium. Afterward the numerical method was used to decompose the inherited integration, so the matrix form of constitution equations was derived. Then through utilizing the Lagrange equation directly, the paper gets the finite element formula. To test the model, the paper calculate the osteoblast's dynamic response under near static load and sinusoidal load at a simple tension beam and a four point bending beam. According to the actual culture condition, the paper set the culture matrix as a biphasic porous medium and set the osteoblast as incompressible viscoelastic medium. The result reveals the viscoelastic behavior very well. Finally, a numerical stimulation software is writed for biphasic porous medium, it postprocesses graphs with OpenGl.