Self-assembly of mineralized collagen composites

This paper presents a review of the current understanding of the structure, self-assembly mechanisms, and properties of mineralized collagen fibril composites in connective tissues, such as in lamellar bones, woven bones, zebrafish skeletal bone, and ivory. Recent work involving biomimetic synthesis of new materials with the structure of mineralized collagen is described. The focus in the paper is mainly on materials containing type I collagen, with mineralization by Ca-P crystals although some other systems are also described. Investigation and simulation of naturally occurring fibril structures can offer some new ideas in the design and fabrication of new functional materials, for applications such as bone grafts or for use as scaffolds in tissue engineering and biomimetic engineering materials. The development of bone grafts based on the mineralization of self-assembled collagen fibrils in vivo and in vitro is an active area of research. This kind of bone graft composite has already shown great promise and success in clinical applications, on account of its compositional and structural similarity to autologous bone. It is suggested that future work in this should focus on both basic theoretical aspects as well as the development of applications. In particular issues including control of morphology, incorporation of foreign ions, interaction with biomolecules, and the assembly of organic and inorganic phases are all still not well understood. In the area of applications, the design of composite materials with a hierarchical structure closer to that of natural hard tissues, and the synthesis of bone grafts and tooth regenerative materials, as well as biomimetic functional materials, are areas currently being examined by many research groups. (C) 2007 Elsevier B.V. All rights reserved.