J. Mater. Sci. Technol. ›› 2020, Vol. 36: 27-36.DOI: 10.1016/j.jmst.2019.04.038

• Research Article • Previous Articles     Next Articles

Synergistic effects of Mg-substitution and particle size of chicken eggshells on hydrothermal synthesis of biphasic calcium phosphate nanocrystals

Wei Cuiab, Qibin Songc, Huhu Suab, Zhiqing Yangab, Rui Yangab, Na Lia*(), Xing Zhangab*()   

  1. a Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    b School of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
    c Department of Plastic Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
  • Received:2019-01-19 Revised:2019-03-06 Accepted:2019-04-25 Published:2020-01-01 Online:2020-02-11
  • Contact: Li Na,Zhang Xing
  • About author:

    1 These two authors contributed equally to this work.

Abstract:

Magnesium (Mg2+) ion plays important roles in biomineralization of bone, teeth and calcium carbonate skeletons. Herein, chicken eggshells mainly comprising of Mg-calcite nanocrystals (Mg/(Mg + Ca) 2.0 mol.%) were used to fabricate biphasic calcium phosphate (BCP), a mixture of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) nanocrystals, through hydrothermal reactions at 200 °C for 24 h. Our results indicated that β-TCP nanocrystals formed through the ion-exchange reactions of Mg-calcite, while HA nanocrystals were mainly produced by dissolution-reprecipitation reactions on the surfaces of eggshell samples in the hydrothermal system. Mg substitution in calcite resulted in formation of β-TCP nanocrystals instead of HA crystals through ion-exchange reactions. BCP samples with different compositions (28.6-77.8 wt.% β-TCP) were produced by controlling particle sizes of eggshells for hydrothermal reactions. The larger particles lead to the larger proportion of β-TCP in the BCP composition. Therefore, Mg substitution and particle size had synergetic effects on the hydrothermal synthesis of BCP using chicken eggshells through balance of ion-exchange and dissolution-reprecipitation reactions. Cell culture results showed that the BCP products were non-cytotoxic to MC3T3-E1 cells, which may be used for bone substitute materials in future.

Key words: Hydrothermal reactions, Ion-exchange, Dissolution-reprecipitation, Nanocrystals, Biphasic calcium phosphate, Bone substitute materials