Stabilization of amorphous calcium carbonate by specialized macromolecules in biological and synthetic precipitates

Authors

  • Joanna Aizenberg,

    Corresponding author
    1. Department of Structural Biology The Weizmann Institute of Science Rehovot 76100 (Israel)
    • Department of Structural Biology The Weizmann Institute of Science Rehovot 76100 (Israel)
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  • Prof. Lia Addadi,

    Corresponding author
    1. Department of Structural Biology The Weizmann Institute of Science Rehovot 76100 (Israel)
    • Department of Structural Biology The Weizmann Institute of Science Rehovot 76100 (Israel)
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  • Prof. Stephen Weiner,

    Corresponding author
    1. Department of Structural Biology The Weizmann Institute of Science Rehovot 76100 (Israel)
    • Department of Structural Biology The Weizmann Institute of Science Rehovot 76100 (Israel)
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  • Prof. Gretchen Lambert

    1. Department of Biological Science California State University Fullerton, CA 92634 (USA)
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  • We thank Dr. J. Hanson for his suggestion to perform the synchrotron X-ray measurements of biogenic amorphous and crystalline powders, Dr. T. F. Koetzle for comments, Y. Freedman for atomic absorption measurements, and Dr. M. Ilan for advice concerning sponge biology. This study was supported by a grant from the US–Israel Binational Science Foundation. S. W. is incumbent of the I. W. Abel Professorial Chair of Structural Biology, and L. A. is incumbent of the Patrick E. Gorman Professorial Chair of Biological Ultrastructure.

Abstract

Composite structures in which amorphous and crystalline phases coexist are formed by some organisms. The spicules of the sponge Clathrina are shown to be composed of a crystalline calcitic core and an outer layer of amorphous CaCO3 (see figure). The latter material, normally a highly unstable mineral, is stabilized in vitro by macromolecules extracted from the outer sponge spicule layer. The combination of crystalline and stabilized amorphous phases may have important implications for materials applications.

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