Chapter 5 - Material and Mechanobiological Considerations for Bone Regeneration

Abstract

Bone graft substitute mechanical and architectural properties maintain a critical role in cellular mechanotransduction and are fundamental design features regulating the migration, lineage, and growth of mesenchymal progenitors and neovascular networks. It is essential that novel bone graft substitutes are designed, fabricated and administered with rigorous consideration for the complex relationships between construct material properties and the transmission of local mechanobiological cues to the regenerative niche. Remarkably, a consensus in the field on even an approximate range of suitable bone implant mechanical properties has not been reached. Consequently, there is a continuum of graft substitutes under active investigation with elastic moduli encompassing seven orders of magnitude. The purpose of this chapter is to examine the state of biomaterial platforms for the treatment of bone defects and to motivate dialog to define appropriate mechanobiological criteria for future bone graft substitute research and development. First, a brief summary of the physiological process of bone regeneration is outlined. Second, material approaches for bone graft substitutes including FDA device classifications and testing considerations are reviewed. Finally, we review in vitro and in vivo evidence elucidating how bone regeneration is regulated by the mechanical environment across multiple length scales.