**3. Scaffold design: the importance of structural and mechanical properties**

The scaffold for tissue engineering must possess structural and mechanical characteristics appropriate to the anatomical site in which it must be implanted and, moreover, must be strong enough to allow its surgical manipulation during implantation. The structural features include macro- and micro-structural properties. The macro-structural properties refer to a temporary 3D architecture, of critical importance, which mimic the ECM and allows cell to maintain their native differentiated phenotypes; while, the micro-structural properties refer to scaffold porosity, pore shape, pore size, and interconnectivity. The mechanical properties include mechanical strength and stiffness.
