Molecular energy dissipation in nanoscale networks of dentin matrix protein 1 is stronglydependent on ion valence

Abstract

The fracture resistance of biomineralized tissues such as bone, dentin, and abalone isgreatly enhanced through the nanoscale interactions of stiff inorganic mineral componentswith soft organic adhesive components. A proper understanding of the interactions thatoccur within the organic component, and between the organic and inorganic components, istherefore critical for a complete understanding of the mechanics of these tissues. In thispaper, we use atomic force microscope (AFM) force spectroscopy and dynamicforce spectroscopy to explore the effect of ionic interactions within a nanoscalesystem consisting of networks of dentin matrix protein 1 (DMP1) (a componentof both bone and dentin organic matrix), a mica surface and an AFM tip. Wefind that DMP1 is capable of dissipating large amounts of energy through anion-mediated mechanism, and that the effectiveness increases with increasing ion valence.