Biomimetic fabrication of collagen-apatite scaffolds for bone tissue regeneration

To develop a suitable substitute material for bone tissue repair and replacement, designing an artificial collagen-apatite scaffold mimicking the composition and hierarchical structure of natural bone has attracted much attention in the past a few years. In the first part of the article, we reviewed conventional approaches in fabrication of biomimeitc collagen-apatite composites involving collagen self-assembly and in situ apatite precipitation in vitro. Then we summarized recent efforts in preparation of hierarchical mineralized collagen fibers using polymers mimicking the role of noncollageneous proteins (NCPs) in collagen fiber biomineralization in vivo. Further, this review highlights the the recent development in the creation of a long-range ordered bone-like structure by combing the liquid property of high concentration collagen molecules with hierarchical mineralization. The second part of the review focuses on the utilization of freeze casting to control the pore size and pore orientation of the scaffold. Finally, potential applications of these biomimetic collagenapatite scaffolds in bone tissue engineering are reviewed. It is believed that scaffolds closely mimic the structure of natural bone may be a promising candidate for bone repair and regeneration.