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Updated: May 23, 2026
09:31
Calcium Carbonate Formation in the Presence of Biopolymeric Additives
Published on: May 14, 2019
Phase transitions in biogenic amorphous calcium carbonate
Yutao U T Gong1, Christopher E Killian, Ian C Olson
1Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706, USA.
Summary
Sea urchin spicules form via amorphous calcium carbonate (ACC) phases. Specific proteins, like SM50, stabilize hydrated ACC, influencing biomineralization and crystal formation.
Area of Science:
- Biomineralization
- Materials Science
- Developmental Biology
Background:
- Crystalline biominerals exhibit non-faceted structures, challenging traditional crystal formation models.
- Existing theories propose amorphous phases as key intermediates in biomineral formation.
Purpose of the Study:
- To investigate the mineral phases involved in sea urchin spicule formation.
- To identify proteins responsible for stabilizing amorphous calcium carbonate during biomineralization.
Main Methods:
- Utilized X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM) to analyze mineral phases.
- Developed an in vitro assay to test protein-mediated mineral phase stabilization.
Main Results:
- Observed a sequential transformation: hydrated amorphous calcium carbonate (ACC·H2O) → dehydrated ACC → calcite.
- Discovered persistent ACC·H2O nanoparticles, indicating inhibited dehydration.
- Identified the SM50 protein as a stabilizer of ACC·H2O in vitro.
Conclusions:
- Protein matrix components, particularly SM50, play a crucial role in stabilizing amorphous calcium carbonate phases during sea urchin biomineralization.
- This stabilization mechanism explains the formation of non-faceted biominerals and offers insights into biomineral structure control.
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