Dehydration-Induced Structural Changes in the Collagen–Hydroxyapatite Interface in Bone by High-Resolution Solid-State NMR Spectroscopy

Abstract

Study of interactions among different components of amorphous biomaterial such as bone is important to understand the mechanism of its formation and biomineralization process and for its unique mechanical properties. In this article, we present dehydration-induced structural changes at the interface of the collagen protein and hydroxyapatite interface in intact mammalian bones by high-resolution solid-state NMR (SSNMR) spectroscopy. With recent advances in SSNMR methodologies, this is the only spectroscopic technique which can provide atomic piercing structural details on amorphous systems such as bone. We performed three SSNMR experiments on bone samples with different degrees of hydration level to probe comparative structural changes. One of the SSNMR experiments is a 13C{31P} Rotational Echo Double Resonance (REDOR) SSNMR experiment which gives an estimate of distances between collagen protein side chain residues and the hydroxyapatite surface in bone. Other SSNMR experiments such as relaxation measure...