Cal Poly Pomona professors Vilupanur Ravi, chemical & materials engineering, and Steve Alas, biological sciences, are investigating a new titanium alloy and the possible long-term benefits for prosthesis patients. From an engineering and biological perspective, their research project studies whether the metal is bio-compatible as an artificial implant.
Although modern medicine has developed advanced artificial limbs and hip replacements, there’s no perfect substitute for the human body. Inevitably, metal prostheses will corrode, cause inflammation, get infected or cause the bone to wear away. Some implants, which are made of stainless steel or other types of titanium, may last just three years while others continue for 15. Younger patients will likely require multiple surgeries in their lifetime to replace the artificial devices.
“Let’s say we find the magic metal that didn’t ever have to be taken out, it could save a lot of money for the medical industry,” Alas says.
The body’s warm, moist and high-salt environment isn’t welcoming for most metals and causes them to corrode, says Ravi. In their experiments, he and five undergraduates expose the titanium alloy, similar variations and other metals to biological media, such as saline solution and observe the results.
“We want to push the metal to corrode and pick the ones that do the best,” Ravi says. “Not only do we determine whether it can handle the environment, we also have to find out if it can carry a heavy load, study how it corrodes and find out the immune response.”
When an artificial implant is introduced, the body’s natural response is to attack the foreign object. A hyper-active immune system can cause inflammation and ultimately reject it. In Alas’ lab, researchers study the immune response by growing cells on the different types of metals. Early results have shown that the titanium alloy “acts better than traditional metals, which means you don’t get as much infection on the surface,” Alas says.
Ravi developed a way to make the new titanium alloys by a melt process technique when he worked as a summer research faculty member at the Wright Patterson Air Force Base in Ohio a few years ago. Lightweight and strong, the alloy had many potential applications. Two years ago, Ravi recruited Alas to investigate the possibility of using the alloy as a bio-impant.
In March, they presented a paper on this subject at the NACE International Corrosion 2009 conference in Atlanta. Students also presented at the conference.