Biomineralization‐Inspired Material Design for Bone Regeneration

Synthetic substitutes of bone grafts, such as calcium phosphate–based ceramics, have shown some good clinical successes in the regeneration of large bone defects and are currently extensively used. In the past decade, the field of biomineralization has delivered important new fundamental knowledge and techniques to better understand this fascinating phenomenon. This knowledge is also applied in the field of biomaterials, with the aim of bringing the composition and structure, and hence the performance, of synthetic bone graft substitutes even closer to those of the extracellular matrix of bone. The purpose of this progress report is to critically review advances in mimicking the extracellular matrix of bone as a strategy for development of new materials for bone regeneration. Lab‐made biomimicking or bioinspired materials are discussed against the background of the natural extracellular matrix, starting from basic organic and inorganic components, and progressing into the building block of bone, the mineralized collagen fibril, and finally larger, 2D and 3D constructs. Moreover, bioactivity studies on state‐of‐the‐art biomimicking materials are discussed. By addressing these different topics, an overview is given of how far the field has advanced toward a true bone‐mimicking material, and some suggestions are offered for bridging current knowledge and technical gaps. Next‐generation materials for bone regeneration, inspired by biomineralization processes, are discussed in this progress report. From the basic components, collagen matrix, and apatite mineral, with emphasis on the recapitulation of intrafibrillar mineralization in vitro, to the scaling up of 2D and 3D constructs, biomaterials are critically appraised for their resemblance with bone's extracellular matrix and their regenerative potential.