An Atomistic Study of the Strength of Protein Mineral Interface of Biological Materials with a Biomimicking Model System at Nanoscale

摘要

Strong biological hard tissues, such as bone, tooth, mineralized tendon and shells, are polymer nanocomposites of protein and mineral. Theoretical and experimental studies showed that the interface should play more dominant roles in the mechanical properties of nanocomposites because of their extremely tiny microstructures. A recent continuum study (Ji, J. Biomech. 41, 259 (2008)) showed that the size and geometry of mineral crystal are crucial to the strength of protein–mineral interface in the nanostructure of biological materials. In this paper, an atomistic biomimicking model system is developed for studying the effect of chain behaviors of protein molecules on the mechanics of this hybrid interface. The interface strength is then calculated by using the molecular dynamics simulations. It is found that the chain behavior of the protein molecules via their periodic stick-slip motion might be an important mechanism to enhance the strength and toughness of the interface. With chemical reaction kinetic theory and Worm-Like Chain model I show that the increase of chain ength can critically raise the strength of the hybrid interface.