16. Tissue Engineering Scaffolds for Bone Repair: General Aspects

Hard tissue repair is a very relevant and challenging area for the emerging fields of tissue engineering and biofabrication due to the very complex three-dimensional structure of bones, which typically include important variations of porosities and related mechanical properties. The need of porous and rigid extra cellular matrices, of structural integrity, of functional gradients of mechanical properties and density, among other requirements, has led to the development of several families of biomaterials and scaffolds for the repair and regeneration of hard tissues, although a perfect solution has not yet been found. Further research is needed to address the advantages of different technologies and materials for manufacturing enhanced, even personalized, scaffolds for tissue engineering studies and extra cellular matrices with outer geometries defined as implants for tissue repair, as the niche composition and 3D structure play an important role in stem cells state and fate. The combined employment of computer-aided design, engineering and manufacturing (also CAD-CAE-CAM) resources, together with rapid prototyping procedures, working on the basis of additive manufacturing approaches, allows for the efficient development of knowledge-based functionally graded scaffolds for hard tissue repair in a wide range of materials and following biomimetic approaches. In this chapter we present some design and manufacturing strategies for the development of knowledge-based functionally graded tissue engineering scaffolds aimed at hard tissue repair. A complete case of study, linked to the development of a scaffold for tibial repair is also detailed to illustrate the proposed strategies.