Cellular solids appear in the body as trabecular bone and lung alveoli. Highly porous, foam-like engineering scaffolds are designed to regenerate tissues such as skin, bone and cartilage. The microstructure and mechanical properties of tissue engineering scaffolds affects the attachment, migration and contractile response of cells. Our group has studied the structure and mechanics of trabecular bone, for instance, modeling the residual stiffness and strength as a result of bone loss in osteoporosis. We have also developed, in conjunction with Professor Ioannis Yannas at MIT and Professor Bill Bonfield at Cambridge University, a bilayer osteochondral scaffold designed for the regeneration of cartilage as well as the underlying bone. We have also studied the mechanics of cell-scaffold interactions such as cell adhesion, contraction and migration on collagen based scaffolds.