Deformation and Failure of Nano-Interfaces in Bone
While non-collagenous proteins at nanoscale interfaces in bone are less than 2 – 3% of bone content by weight, they contribute to more than 30% of the fracture toughness. A major gap in the quantitative understanding of the role of interfaces in bone, largely due to limitations in probing their nanoscale dimension, has resulted in ongoing controversies and abundant hypotheses on their role and function, arguably going back to centuries to the original work from Galileo. Molecular dynamics (MD) simulation has been a powerful tool to study the mechanisms of deformation that happen inside biological materials on the nano-meter scale. For the first time, MD simulation has been implemented to reveal the intricate structure and deformation mechanisms of nano-interface complexes in bone. The model was developed based on experimental evidence on the nano-interface reported in the literature. The results showed that the specific energy of the nano-interface is several times larger than in other natural materials. The reasons behind the outstanding properties of the nano-interface are revealed and discussed in detail. The findings of the present work provide a better understanding of bone nanomechanics. In addition, marvelous properties and unique deformation mechanisms of the nano-interface may facilitate the design of novel biomaterials in the future. Diseases such as osteoporosis and genotypes may significantly compromise the composition and mechanics of the nano-interface and result in degradation of mechanical properties of bone. Hence, the development of standard tests for assessing composition and quality of the nano-interface in bone has to be done.