Particle-Attachment-Mediated and Matrix/Lattice-Guided Enamel Apatite Crystal Growth. Academic Article uri icon


  • Tooth enamel is a hard yet resilient biomaterial that derives its unique mechanical properties from decussating bundles of apatite crystals. To understand enamel crystal nucleation and growth at a nanoscale level and to minimize preparation artifacts, the developing mouse enamel matrix was imaged in situ using graphene liquid cells and atomic resolution scanning transmission electron and cryo-fracture electron microscopy. We report that 1-2 nm diameter mineral precipitates aggregated to form larger 5 nm particle assemblies within ameloblast secretory vesicles or annular organic matrix subunits. Further evidence for the fusion of 1-2 nm mineral precipitates into 5 nm mineral aggregates via particle attachment was provided by matrix-mediated calcium phosphate crystal growth studies. As a next step, aggregated particles organized into rows of 3-10 subunits and developed lattice suprastructures with 0.34 nm gridline spacings corresponding to the (002) planes of apatite crystals. Mineral lattice suprastructures superseded closely matched organic matrix patterns, suggestive of a combination of organic/inorganic templates guiding apatite crystal growth. Upon assembly of 2-5 nm subunits into crystal ribbons, lattice fringes indicative of the presence of larger ordered crystallites were observed surrounding elongating crystal ribbons, presumably guiding the c-axis growth of composite apatite crystals. Cryo-fracture micrographs revealed reticular networks of an organic matrix on the surface of elongating enamel crystal ribbons, suggesting that protein coats facilitate c-axis apatite crystal growth. Together, these data demonstrate (i) the involvement of particle attachment in enamel crystal nucleation, (ii) a combination of matrix- and lattice-guided crystal growth, and (iii) fusion of individual crystals via a mechanism similar to Ostwald ripening.

published proceedings

  • ACS Nano

altmetric score

  • 1

author list (cited authors)

  • Jokisaari, J. R., Wang, C., Qiao, Q., Hu, X., Reed, D. A., Bleher, R., ... Diekwisch, T.

citation count

  • 14

complete list of authors

  • Jokisaari, Jacob R||Wang, Canhui||Qiao, Qiao||Hu, Xuan||Reed, David A||Bleher, Reiner||Luan, Xianghong||Klie, Robert F||Diekwisch, Thomas GH

publication date

  • March 2019