Could osteoporosis be reversed by using a biocomposite material as a framework for bone tissue regeneration? Discoveries made recently through quantitative 3-D supramolecular imaging, a tool adapted by NC State’s Dr. Richard J. Spontak, make it a very real possibility.

Spontak, a professor of chemical engineering as well as materials science and engineering, announced the imaging technique early last year as a method to create three-dimensional images for scientific visualization, study, and measurement of nanostructured polymers at the nanometer level. Recently, he and his collaborators used the technique to identify quantitative similarities between synthetic polymers and bone tissue.

To reveal these similarities, Spontak and an international, multidisciplinary research team used quantitative 3-D imaging techniques to compare the structural patterns of two kinds of polymer systems with samples of trabecular bone—the porous bone found in the spine and articulating joints. The investigators focused on the unique characteristics shared by these manufactured and naturally-occurring “bicontinuous morphologies”—described as asymmetrical, irregularly channeled spatial structures resembling the inside of a sponge. What intrigued Spontak and his colleagues was the discovery that structural characteristics of sponge-like synthetic polymers and trabecular bone are strikingly similar, despite substantial differences in origin and scale.

“With this knowledge, we can start to think of designing the polymer equivalent of bone at nanoscale dimensions,” Spontak said. “The polymer could be used to initiate finer, but similar structure off existing bone. Because the polymer is more highly interconnected at smaller scales and could serve as a template for stronger structural materials, it could help people who need bone grafts, as well as people who suffer from osteoporosis.”

The understanding of the nanoscale molecular structure that led to this discovery is related directly to the development of quantitative 3-D imaging methods. When the method was announced, it was valued primarily as a tool for research scientists, and its potential for application was not fully realized. Scientists no longer had to rely on mathematical models that only approximate the potentially complex nature of nanostructured polymers. With 3-D imaging, investigators are able to “see” inside and quantify these nanostructures for the first time, much as an MRI allows physicians to see inside their patients in three-dimensions. This makes the technique ideally suited for studying the design or “evolution” of nanostructures, as well as defect formation.

“Learning more about the structure, connectivity, and material properties of nanostructured polymers is important,” Spontak said, “but the possibility of extending that knowedge to other systems in ways not apparent at the time of discovery is truly exciting.” This imaging technique and the accompanying methods of analysis allow in-depth study of any nanostructured polymer at length scales greater than about one nanometer (or about one thousandth of the width of a human hair). They also provide a direct approach for developing relationships between structure and properties of interest in commercial applications.

“All research knowledge is valuable,” Spontak says, “even if it can’t be used immediately. I’m confident that people will come to appreciate the utility and potential of this technique more and more, especially in light of the growing importance of nanotechnology in today's society.”

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