MECHANICS OF ACTIVE POROUS MEDIA: BONE TISSUE ENGINEERING APPLICATION

In orthopedics, a currently developed technique for large graft hybrid implants consists of using porous and biocompatible scaffolds seeded with a patient's bone cells. Successful culture in such large implants remains a challenge for biologists, and requires strict control of the physicochemical and mechanical environments achieved by perfusion within a bioreactor for several weeks. This perfusion, with a nutritive fluid carrying solute ingredients, is necessary for the active cells to grow, proliferate, differentiate, and produce extracellular matrices. An understanding and control of these processes, which lead to substrate degradation and extracellular matrix remodeling during the in vitro culture phase, depend widely on the success in the realization of new orthopedic biomaterials. Within this context, the analysis of the interactions between convective phenomena of hydrodynamic origin and chemical reactions of biological order which are associated to these processes is a fundamental challenge in the framework of bone tissue engineering. In order to better account for the different intricate processes taking place in such a sample and to design a relevant experimental protocol leading to the definition of an optimal tissue implant, we propose one- and two-dimensional theoretical models based on transport phenomena in porous active media.