TY - JOUR

T1 - Osteopontin Stabilizes Metastable States Prior to Nucleation during Apatite Formation

AU - Ibsen, Casper Jon Steenberg

AU - Gebauer, Denis

AU - Birkedal, Henrik

N1 - Funding information: Part of this study was made possible by funding from COST action TD0903. The ultracentrifugation experiments and subsequent conversion of raw data to sedimentation coefficients were performed by Marius Schmid; we thank him for his kind assistance. We also want to acknowledge Dr.'s John K. Berg and Matthias Kellermeier for general assistance performing and interpreting the titration experiments. John Berg also helped record the TEM micrographs. This work is supported by the Danish Council for Independent Research/Technology and Production Sciences and by the Danish Agency for Science, Technology and Innovation (DANSCATT). We acknowledge MAXLAB, Lund, Sweden for the provision of synchrotron radiation beamtime at the I7-11 beamline.

PY - 2016

Y1 - 2016

N2 - Osteopontin, which is a phosphoprotein with strong ties to in vivo bone mineralization, is shown to change the precipitation pathway of calcium phosphate. We show that the presence of the phosphoprotein, even in minute concentrations, can stabilize an otherwise oversaturated mixture against precipitation. At moderate concentrations, we find that the protein introduces a new intermediate state into the reaction pathway leading to apatite formation. This new intermediate was found to share many characteristics of a coacervate or polymer-induced liquid-like precursor (PILP) phase. Our results show that these types of complex phases should be considered when discussing the mechanisms of bone mineralization on a subcellular level.

AB - Osteopontin, which is a phosphoprotein with strong ties to in vivo bone mineralization, is shown to change the precipitation pathway of calcium phosphate. We show that the presence of the phosphoprotein, even in minute concentrations, can stabilize an otherwise oversaturated mixture against precipitation. At moderate concentrations, we find that the protein introduces a new intermediate state into the reaction pathway leading to apatite formation. This new intermediate was found to share many characteristics of a coacervate or polymer-induced liquid-like precursor (PILP) phase. Our results show that these types of complex phases should be considered when discussing the mechanisms of bone mineralization on a subcellular level.

UR - http://www.scopus.com/inward/record.url?scp=85006282651&partnerID=8YFLogxK

U2 - 10.1021/acs.chemmater.6b01088

DO - 10.1021/acs.chemmater.6b01088

M3 - Article

VL - 28

SP - 8550

EP - 8555

JO - Chemistry of materials

JF - Chemistry of materials

SN - 0897-4756

IS - 23

ER -