US researchers have described for the first time how minerals come together at the molecular level to form bones and other hard tissues, like teeth and enamel.
The University of Illinois Chicago researchers describe their experiments in Science Advances—which captured high-resolution, real-time images of the mineralisation process in an artificial saliva model—and their discovery of distinct pathways that support bone and teeth formation, or biomineralisation.
“Until now these pathways, particularly at the early stages when molecules are first starting to organise into a structure, have not been understood clearly,” Professor Reza Shahbazian-Yasser said.
Professor Shahbazian-Yasser and his colleagues observed that both direct and indirect formations of hydroxyapatite crystals—the foundation of hard tissues—can be achieved by local variations in energetic pathways for nucleation and growth.
“The control over the dissolution of amorphous calcium phosphate affects the assembly of hydroxyapatite crystals into larger aggregates,” Professor Shahbazian-Yasser said.
“Using technology developed at UIC, we found evidence that these pathways coexist simultaneously—explaining why different groups had reported seemingly different or opposite results. In addition, we now understand how hydroxyapatite materials nucleate and grow on amorphous calcium phosphate templates. The control over the nucleation and growth of hydroxyapatite will aid in developing new drugs and medical treatments to heal lost or broken bone faster or cure tooth cavities.”
To capture the images, the researchers used a unique micro-device that made it possible to use electron microscopy with a liquid model. Using this method, the researchers were able to monitor chemical reactions in the model on the smallest scale.
“Our study provides clear, new evidence of how minerals organise and grow into bone materials, and this finding has many important implications for further research on bone or teeth healing,” Professor Shahbazian-Yasser said.