Two Paths to Healing Bones

Like many other materials, bone varies in size and composition, changing over time. But it can also regenerate and repair itself. Two Beckman researchers are using engineering skills and technology to unravel the secrets of its complex structure. 

Two hundred and six bones in an adult human body make up the skeleton, one of the body’s vital mechanical systems. Beckman faculty members Amy Wagoner Johnson of the Bioimaging Science and Technology Group and Iwona Jasiuk of the 3D Micro- and Nanosystems Group are delving deeper by exploring the internal structure of bone itself. And while they share the broader goal of improving medicine and treatment for diseases and traumatic injuries, they are taking two different paths to arrive there. 

Wagoner Johnson’s main work with bone involves creating ceramic “scaffolds” to heal large gaps in bone. These gaps can occur either with serious trauma or the removal of diseased bone due to such diseases as osteoporosis or bone cancer. 

“If the defect is too big, the bone won’t bridge the defect on its own,” Wagoner Johnson said. “So the idea is to put a scaffold in there that allows bone to grow in, called an osteoconductive structure. And there are factors that don’t just allow the bone to grow in, but actually encourage it to do so, and so we try to figure out what kind of variables encourage bone formation.” 

There are a quite a lot of these variables. The material of the scaffold is a calcium phosphate material called hydroxyapatite, which is a more natural material than the polymers that most other bone scaffolds are made of and more likely to be accepted by the body. The structure of the scaffold also has a large effect on how well the bone grows into it (if at all), and Wagoner Johnson’s team found that the microstructure plays an important role. 

“Microporosity—in addition to larger scale porosity—turns out to be important, so the scaffolds we make are hierarchical, in a way, similar to natural bone,” Wagoner Johnson said. 

Jasiuk is also looking at the structural properties of bone as a material, but in a slightly different way. While she also studies bone regeneration, her main focus is in how bone structure changes when it is affected by age or disease, especially osteoporosis, a disease that affects more than 10 million people in the United States today. 

“The idea is that bone has a very complex structure at different hierarchical scales, and the structural and compositional properties of bones change with age,” Jasiuk said. “We are interested in the structure of healthy bone and deviations from it, with the hope of finding or assessing medications for curing or treating it or for early diagnosis of osteoporosis.” 

Her work involves aging bone, diseased bone, bone regeneration, and the growth of bone due to mechanical motion such as exercise. She studies bone both as a structural material, and also as a biological material that changes both structure and composition with different environments and stimuli. 

“We are investigating fundamentally what processes are taking place during regeneration,” Jasiuk said. “Most studies focus on the final outcome— whether regeneration takes place or not. We’ve showed that you can regenerate bone, using a specific approach, and now we want to understand fundamentally what takes place in a successful regeneration as opposed to a regeneration that is not successful.” 

Both research groups have the same long-term goal: to find effective and safe methods for repairing or treating broken or diseased bone. 

“I feel like I’m doing something good for somebody,” Wagoner Johnson said. “I think it’s really neat to be able to use engineering skills and technology and apply them to biomedical problems. It’s so much more motivating to me to have that application.” 

For Jasiuk, the biological connection was a pleasant surprise. 

“I was always very interested in biology and biological applications,” Jasiuk said, “but at the time when I was making decisions about my studies, I did not know I had that option. I enjoy it very much.”

This article was originally published in the Spring 2014 issue of the Engineering at Illinois magazine.