Molecular dynamics simulation of mechanical behavior of osteopontin-hydroxyapatite interfaces.
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.
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.
Zheng Bo
ZB
Lai
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.
Mingchao
M
Wang
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.
Cheng
C
Yan
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.
Adekunle
A
Oloyede
D001665:Binding Sites; D003198:Computer Simulation; D017886:Durapatite / Q000737:chemistry*; D004735:Energy Transfer; D008956:Models, Chemical; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D053495:Osteopontin / Q000737:chemistry* / Q000648:ultrastructure*; D011485:Protein Binding; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
D053495:Osteopontin; D017886:Durapatite
Hydroxyapatite; Interface; Mechanical property; Molecular dynamics; Osteopontin