Collagen intrafibrillar mineralization as a result of the balance between osmotic equilibrium and electroneutrality.
Mineralization of fibrillar collagen with biomimetic process-directing agents has enabled scientists to gain insight into the potential mechanisms involved in intrafibrillar mineralization. Here, by using polycation- and polyanion-directed intrafibrillar mineralization, we challenge the popular paradigm that electrostatic attraction is solely responsible for polyelectrolyte-directed intrafibrillar mineralization. As there is no difference when a polycationic or a polyanionic electrolyte is used to direct collagen mineralization, we argue that additional types of long-range non-electrostatic interaction are responsible for intrafibrillar mineralization. Molecular dynamics simulations of collagen structures in the presence of extrafibrillar polyelectrolytes show that the outward movement of ions and intrafibrillar water through the collagen surface occurs irrespective of the charges of polyelectrolytes, resulting in the experimentally verifiable contraction of the collagen structures. The need to balance electroneutrality and osmotic equilibrium simultaneously to establish Gibbs-Donnan equilibrium in a polyelectrolyte-directed mineralization system establishes a new model for collagen intrafibrillar mineralization that supplements existing collagen mineralization mechanisms.
State Key Laboratory of Military Stomatology &National Clinical Research Center for Oral Diseases &Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
Li-Na
LN
Niu
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Sang Eun
SE
Jee
State Key Laboratory of Military Stomatology &National Clinical Research Center for Oral Diseases &Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
Kai
K
Jiao
Department of Biological Structure, University of Washington, Seattle, Washington 98195, USA.
Lige
L
Tonggu
Department of Biological Structure, University of Washington, Seattle, Washington 98195, USA.
Mo
M
Li
Department of Biological Structure, University of Washington, Seattle, Washington 98195, USA.
Liguo
L
Wang
Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710054, China.
Yao-Dong
YD
Yang
Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710054, China.
Ji-Hong
JH
Bian
Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, 40125 Bologna, Italy.
Lorenzo
0000-0001-7621-226X
L
Breschi
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Seung Soon
SS
Jang
State Key Laboratory of Military Stomatology &National Clinical Research Center for Oral Diseases &Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
Ji-Hua
JH
Chen
The Dental College of Georgia, Augusta University, Augusta, Georgia 30912, USA.
David H
DH
Pashley
The Dental College of Georgia, Augusta University, Augusta, Georgia 30912, USA.
Franklin R
FR
Tay
D003198:Computer Simulation; D004573:Electrolytes / Q000737:chemistry; D024022:Fibrillar Collagens / Q000737:chemistry* / Q000648:ultrastructure*; D008903:Minerals / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D009997:Osmotic Pressure; D055672:Static Electricity
D004573:Electrolytes; D024022:Fibrillar Collagens; D008903:Minerals