Amorphous solid

Amorphous calcium carbonate

Engineering

Nanoparticle

Materials science

Chemical engineering

Biomineralization

Nanotechnology

Organic chemistry

Calcium carbonate

Crystallography

Chemistry

Nucleation

Science

Biogenic calcium carbonate forms the inorganic component of seashells, otoliths, and many marine skeletons, and its formation is directed by an ordered template of macromolecules. Classical nucleation theory considers crystal formation to occur from a critical nucleus formed by the assembly of ions from solution. Using cryotransmission electron microscopy, we found that template-directed calcium carbonate formation starts with the formation of prenucleation clusters. Their aggregation leads to the nucleation of amorphous nanoparticles in solution. These nanoparticles assemble at the template and, after reaching a critical size, develop dynamic crystalline domains, one of which is selectively stabilized by the template. Our findings have implications for template-directed mineral formation in biological as well as in synthetic systems.

The Initial Stages of Template-Controlled CaCO <sub>3</sub> Formation Revealed by Cryo-TEM

The Initial Stages of Template-Controlled CaCO 3 Formation Revealed by Cryo-TEM

The Initial Stages of Template-Controlled CaCO ₃ Formation Revealed by Cryo-TEM