Molecular dynamics simulation of mechanical behavior of osteopontin-hydroxyapatite interfaces

Zheng Bo Lai; Mingchao Wang; Cheng Yan; Adekunle Oloyede

doi:10.1016/j.jmbbm.2014.04.002

Molecular dynamics simulation of mechanical behavior of osteopontin-hydroxyapatite interfaces

J Mech Behav Biomed Mater. 2014 Aug:36:12-20. doi: 10.1016/j.jmbbm.2014.04.002. Epub 2014 Apr 13.

Authors

Zheng Bo Lai¹, Mingchao Wang¹, Cheng Yan², Adekunle Oloyede¹

Affiliations

¹ School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia.
² School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, QLD 4001, Australia. Electronic address: c2.yan@qut.edu.au.

PMID: 24786380
DOI: 10.1016/j.jmbbm.2014.04.002

Abstract

Bone is characterized with an optimized combination of high stiffness and toughness. The understanding of bone nanomechanics is critical to the development of new artificial biological materials with unique properties. In this work, the mechanical characteristics of the interfaces between osteopontin (OPN, a noncollagenous protein in extrafibrillar protein matrix) and hydroxyapatite (HA, a mineral nanoplatelet in mineralized collagen fibrils) were investigated using molecular dynamics method. We found that the interfacial mechanical behavior is governed by the electrostatic attraction between acidic amino acid residues in OPN and calcium in HA. Higher energy dissipation is associated with the OPN peptides with a higher number of acidic amino acid residues. When loading in the interface direction, new bonds between some acidic residues and HA surface are formed, resulting in a stick-slip type motion of OPN peptide on the HA surface and high interfacial energy dissipation. The formation of new bonds during loading is considered to be a key mechanism responsible for high fracture resistance observed in bone and other biological materials.

Keywords: Hydroxyapatite; Interface; Mechanical property; Molecular dynamics; Osteopontin.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Binding Sites
Computer Simulation
Durapatite / chemistry*
Energy Transfer
Models, Chemical*
Molecular Conformation
Molecular Dynamics Simulation*
Osteopontin / chemistry*
Osteopontin / ultrastructure*
Protein Binding
Stress, Mechanical
Surface Properties
Tensile Strength

Substances

Osteopontin
Durapatite