Utilization of Proteins and Peptides to Create Organic-Hydroxyapatite Hybrids

Background: Various types of proteins play important roles in the biomineralization of hydroxyapatite (HAp, Ca10(PO4)6(OH)2). The resulting organic-HAp nanohybrids have highlyorganized hierarchical structures that show unique morphological, structural, and mechanical properties. By mimicking the biomineralization process, organic-HAp hybrid materials have been created by utilizing proteins and peptides. Objectives: In this review, firstly the roles of proteins in HAp mineralization in vivo are briefly explained. Recent progresses in the creation of organic-HAp hybrids through the utilization of proteins and peptides are then described. Results: Roles of collagen and amelogenin on the formation of bones and teeth were explained. Then, recent advances, including those by the authors, in the creation of organic-HAp hybrids through the utilization of these proteins, their derivatives, and synthetic peptides, including engineering- isolated ones, were reviewed. Conclusion: Organic-HAp hybrid materials have been intensively created by utilizing proteins and peptides. Among them, engineering-isolated or rationally designed peptides and their derivatives represent future promising building components for organic-HAp hybrids with precise hierarchical structures. Not only the excellent functions of the resultant hybrids materials, but also the creation of materials by biomimetic synthetic processes at a low cost and environmental burden are important for sustainable industrial development.