Carnegie Mellon University
March 26, 2019

'Using the Power of Chemistry' to Heal Our Broken Bones

By Ben Panko

When she was in graduate school at the Massachusetts Institute of Technology, Assistant Professor of Chemistry Stefanie Sydlik suffered a cartilage injury. This got the chemistry major to start thinking about and researching the biological processes behind healing in the body, especially the healing of bones. In a new paper in the journal Proceedings of the National Academy of Sciences, Sydlik demonstrates how graphite ­— the same substance we fill our pencils with ­— can be employed to repair severe bone fractures more effectively than current technology.

"What we're trying to do is make this obsolete," Sydlik said, pointing to an x-ray of her wrist, where she had a titanium plate implanted after breaking it in 2016. Traumatic bone injuries like that are commonly seen on the battlefield or in cycling, which Sydlik is passionate about. This metallic hardware is often used as a scaffold for a person's bone to heal around in severe injuries, in which it’s more likely that the healing bones won’t be properly aligned or have adequate blood supply. However, its permanence inside a person can damage the tissue around it; this also makes it unsuitable for children with growing bodies.

"Bone is a super interesting material in the body because we have the ability to regenerate it," Sydlik said. "The question is: How do we tap into that natural healing response so we can heal major fractures the same as minor fractures?"

The answer for Sydlik and her team turned out to be graphite, the "lead" one can find in most pencils. By modifying graphene with calcium phosphate, the researchers were able to create a material that avoids rejection by mimicking the composition of bone found in our bodies and degrades when it's no longer needed. Even more beneficially, these calcium phosphate graphene scaffolds, which were tested in mice, release signals that instruct the body's stem cells to heal a person's bone in major fractures the same way they do for minor fractures.

"We're using the power of chemistry to tell the biology what to do," Sydlik said.

Sydlik's team, which includes graduate student Anne Arnold and postdoctoral associate Brian Holt, is now collaborating with engineers such as Associate Professor of Biomedical Engineering and Materials Science and Engineering Adam Feinberg, an expert in 3D bioprinting, to shape their calcium phosphate graphene into scaffolds with controllable geometry that can be molded to implant where a person has fractured a bone. They also collaborated with Cato Laurencin and Leila Daneshmandi with the University of Connecticut.

This study was funded by a NIH Director’s Pioneer Award from the U.S. National Institutes of Health and by startup grants from Carnegie Mellon University.