Article pubs.acs.org/JPCC
Accurate Force Field Parameters and pH Resolved Surface Models for Hydroxyapatite to Understand Structure, Mechanics, Hydration, and Biological Interfaces Tzu-Jen Lin† and Hendrik Heinz*,†,‡ †
Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
‡
S Supporting Information *
ABSTRACT: Mineralization of bone and teeth involves interactions between biomolecules and hydroxyapatite. Associated complex interfaces and processes remain difficult to analyze at the 1 to 100 nm scale using current laboratory techniques, and prior apatite models for atomistic simulations have been limited in the representation of chemical bonding, surface chemistry, and interfacial interactions. In this contribution, an accurate force field along with pH-resolved surface models for hydroxyapatite is introduced to represent chemical bonding, structural, surface, interfacial, and mechanical properties in quantitative agreement with experiment. The accuracy is orders of magnitude higher in comparison to earlier models and facilitates quantitative monitoring of inorganic-biological assembly. The force field is integrated into the AMBER, CHARMM, CFF, CVFF, DREIDING, GROMACS, INTERFACE, OPLS-AA, and PCFF force fields to enable realistic simulations of apatite-biological systems of any composition and ionic strength. Specific properties that are reproduced well in comparison to experiment include lattice constants (
