- PhD Mechanical Engineering 2011
For Tolou Shokuhfar, developing better surgical implants had always been about engineering. Then an orthopedic surgeon approached her after she gave a talk on her work.
She recalls the conversation. "You are changing people's lives," said the surgeon, a faculty member at the Marshall University School of Medicine. "You never want to see a patient with an infected implant it is so hard on them. When they come to see me, we cry together."
Until that moment, Shokuhfar confesses, she hadn't given the matter much thought. "I was happy to be solving a serious problem, but the actual patients in the hospital were so far from my reality in the lab. Now I tell my students, 'Guys, remember, we are really helping people.’"
Titanium and its alloys have a leg up on all other materials used to make the orthopedic implants used by surgeons to repair damaged bones and joints. They are light, strong, and virtually inert. Most of the time, titanium implant surgeries are successful. But if an infection sets in, or if the bone simply fails to heal properly, the results can be agonizing.
Since she was a graduate student, Shokuhfar, an assistant professor of mechanical engineering-engineering mechanics, has been researching a new surface for titanium implants to help head off such disasters. Using a simple procedure she developed ("You could do it in your kitchen sink."), she etches nanotubes into the titanium dioxide that naturally encases metallic titanium.
To bone cells, those nanotubes feel like home. In lab tests, osteoblasts have clung to them and proliferated far better than to plain titanium or even the roughened titanium used on some implants. This may be because the nanotube surface forms a regular lattice, not unlike the matrix that forms the basis of bone tissue.
Ironically, early tests show that bacteria are repelled by the nanotube surface. Now scientists at Beaumont Hospital in metro-Detroit are conducting additional research into how MRSA, an antibiotic-resistant form of staphylococcus, reacts to the surface. And scientists at the University of Tennessee are investigating its effect on bacteria that causes the gum disease periodontitis.
Why periodontitis? Shokuhfar is also working with colleagues at the University of Chicago's College of Dentistry to develop better dental implants. They are posts, usually made of titanium, that are surgically placed into the jawbone and topped with artificial teeth. Occasionally, they fail or become infected; the same nanotube coating that could improve knee replacements could also brighten somebody's smile.
The nanotube surface has yet another attribute that Shokuhfar believes could reduce the failure rate in all types of titanium implants. It can serve as a drug-delivery system for antibiotics, anti-inflammatory drugs, or even silver nanoparticles. "Silver has antimicrobial properties, and we are capable of obtaining a dose that can kill microbes but would not hurt healthy cells and tissues," she said.
On the horizon are animal tests and eventually clinical trials. Because the nanotubes are simply another form of titanium dioxide, Shokuhfar hopes the approval process will be short.
This profile appeared in the article "Good to the Bone" by Marcia Goodrich, in the 2014 Issue of Research