Bioinspired Approaches to Bone
Bone is a complex organ that acts as a biomechanical and protective scaffold in conjunction with the musculature; regulates calcium and phosphate ion homeostasis; and is an endocrine organ involved with energy homeostasis. The ability of bone self-repair, however, is limited to small defects, creating the need to develop bone-replacement materials that mimic its properties and restore the function of the native tissue. One of the major challenges facing material scientists in recreating bone-replacement materials comes from the complexity of the structure of bone, which in turns gives rise to its mechanical properties. Furthermore, these properties are calibrated according to the biological context, such that different types of bones performing different functions will display different architectures, across many length scales. In this chapter, we will discuss the different materials used for producing biomimetic bone-replacement materials that combine osteoconductivity, osteoinductivity, resorbability and osseointegration. These include biopolymers such as collagen and silk; synthetic polymers; calcium phosphate cements; and the use of wood as a template for hierarchical synthetic materials. We will further discuss cell–scaffold interactions and emerging fabrication technologies as methods to produce scaffolds with pre-designed and controlled shapes, sizes, and internal and external architectures.