U. PITTSBURGH (US) — Protein molecules that self-assemble like stepping blocks and then stabilize in a connect-the-dot fashion give tooth enamel its unique combination of hardness and resiliency.
Researchers believe the findings, reported in Proceedings of the National Academy of Sciences, may translate to nanoscale development of a variety of biomaterials, including those used for restorative dentistry.
Dental enamel is the most mineralized tissue in the body and combines high hardness with resilience, says Elia Beniash, professor of oral biology at the University of Pittsburgh. Those properties are the result of its unique structure, which resembles a complex ceramic microfabric.
“Enamel starts out as an organic gel that has tiny mineral crystals suspended in it,” he says. “In our project, we recreated the early steps of enamel formation so that we could better understand the role of a key regulatory protein called amelogenin in this process.”
After assembling by way of small oligomeric building blocks into higher-order structures, amelogenin proteins then are able to stabilize tiny particles of calcium phosphate, which is the main mineral phase in enamel and bone, and organize them into parallel arrays.
Once arranged, the nanoparticles fuse and crystallize to build the highly mineralized enamel structure.
“The relationship isn’t clear to us yet, but it seems that amelogenin’s ability to self-assemble is critical to its role in guiding the dots, called prenucleation clusters, into this complex, highly organized structure,” Beniash says.
“This gives us insight into ways that we might use biologic molecules to help us build nanoscale minerals into novel materials, which is important for restorative dentistry and many other technologies.”
Researchers from the University of Michigan and the Forsythe Institute in Cambridge, Mass. contributed to the study, which was funded by the National Institutes of Health and the Commonwealth of Pennsylvania.
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