| A triphasic mixture theory, combined with numerical and experimental efforts, was taken in this thesis to investigate the comprehensive mechano-electrochemical (MEC) behaviors of articular cartilage. The motivation of these studies is to better understand the mechanism behind functions, physiology and pathology of cartilage tissue. The identification of such mechanism will provide tremendous potential for diagnosis, treatment and prevention of pathological conditions such as osteoarthritis.; First, a mixed finite element formulation was developed for the triphasic mixture theory. Such a formulation provides a powerful tool to facilitate the theory application to charged hydrated soft tissues. Base on that, the effect of the fixed charge density (FCD) on the loading capacity and the electrical potential responses of articular cartilage was investigated in typical confined compression and permeation experimental configurations, and the natural and deformation-induced FCD non-uniformity and its implications to cartilage functional MEC behaviors were explored. The significant contribution of the FCD to the tissue apparent material properties, such as apparent Young's modulus and Poisson's ratio, was addressed through an unconfined compression study. As a practical experimental technique, the triphasic indentation was developed to detect both the non-destructive mechanical properties and the electrochemical property (the FCD) of articular cartilage.; The comprehensive MEC events inside the cartilage tissue are the signals the chondrocytes sense. Using a two-scale triphasic finite element cell-matrix interaction model, such events were examined for typical in vitro experimental configurations. This study enhances the understanding of the signal transduction mechanism of the chondrocytes and provides guidance in tissue engineering exploration. Therefore, toward the end of the thesis, dynamic permeation was analyzed as a candidate bioreactor for the purpose of the inhomogeneous tissue culture. |
