Collagenous Mineralized Tissues: Composition, Structure, and Biomineralization

Abstract

Mineralized tissues play multiple essential roles in the body, including locomotion, mechanical protection and support of the soft tissues, mastication; sense of gravity and linear acceleration, mineral ion depot, and others. The vast majority of mineralized tissues in the human body, such as bone, dentin, and cementum, belong to the family of collagenous mineralized tissues (CMTs). Two major components of these tissues are collagen type I fibrils and nonstoichiometric carbonated apatite nanocrystals which comprise the mineralized collagen fibrils—the basic building blocks of CMTs. The mineralized collagen fibrils organize into a variety of structural patterns at several hierarchical levels from nano- to macroscale. In addition to the two major components, CMTs contain a number of noncollagenous extracellular matrix components, including proteins and proteoglycans, carbohydrates, and lipids. These noncollagenous biomolecules play a role in the regulation of the mineralization process of CMTs. CMTs are biogenic hierarchical nanocomposite materials and understanding of their formation and function requires interdisciplinary efforts of researchers from different fields of study including chemists, material scientists, and biologists. Not only these studies help us to understand how mineralized tissues form and function, they also provide inspiration for the design of novel materials using principles learned in nature. This chapter provides a general overview of the composition, structural organization, and biomineralization of CMTs with the emphasis on recent advances in the field.