Effect of agar hydrogel and magnesium ions on the biomimetic mineralization of calcium carbonate

Here, agar hydrogel was selected as diffusion medium and template to control the biomimetic mineralization of calcium carbonate (CaCO3). Due to three dimensional network structures and abundant functional groups (such as, hydroxyl groups), Ca2+ ions were uniformly distributed in the network and electrostatically attracted. The diffusion speed and range of CO- ions were mediated by the concentration of hydrogel medium. Under the synergistic effect of Mg2+ ions, the crystal CaCO3 was induced by gas phase diffusion method in the hydrogel system. The results showed that the concentrations of Mg2+ ions and agar hydrogel had no obvious effect on the calcite phase of CaCO3, but the morphologies and sizes changed with concentrations of medium and Mg2+ ions. Attribute to template effect, the crystallization behavior and growth rate of CaCO3 crystals were regulated. Since Mg2+ ions were easily adsorbed on the surfaces of unit cell, the unique structure of CaCO3 was precisely controlled. This study provides a useful reference and inspiration for the understandings of the contributions of ion supply rate in bio-mineralization and hydrogel medium in biomimetic mineralization.

Automated summary

Agar hydrogel was used as a diffusion medium and template to control the biomimetic mineralization of CaCO3. The concentration of hydrogel medium mediated the diffusion speed and range of CO- ions, while the presence of Mg2+ ions resulted in the induction of crystal CaCO3. The study showed that hydrogel concentration and Mg2+ ion concentration did not affect the calcite phase of CaCO3, but influenced the morphology and size of the crystals. The research provides valuable insights into the roles of ion supply rate and hydrogel medium in biomimetic mineralization.