Bone responses to biomaterials

The field of bone tissue engineering has been growing over time, implementing strategies to induce bone regeneration in diverse pathological settings. To this end, scaffolds made of different biomaterials are exploited for their osteoinductive, osteoconductive, and osteogenic properties and for the delivery of factors to promote tissue regeneration. This process involves intense physical and molecular interactions between the implanted biomaterial and resident cells in the bone tissue or cells recruited from the periphery to the implanted site. The implanted biomaterials, according to their physicochemical properties, elicit an active response from skeletal cells (osteoclasts, osteoblasts, osteocytes, and their precursors) and, more importantly, from immune cells, including macrophages, neutrophils, dendritic cells, and lymphocytes, and endothelial cells. In this chapter, we will address the cellular events that follow the biomaterial implantation in bone and the challenges in reproducing or tuning the complex tissue microenvironment for successful tissue regeneration.