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The researchers grew the nanowires through thermal oxidation of a mix of materials and gases inside a furnace. At temperatures of about 1,300 degrees Fahrenheit, fine filaments of titanium dioxide rose from the smooth titanium surface. In addition, each wire developed a protective coating of aluminum dioxide at its surface — an effect the researchers could not explain, as they were working with pure titanium.
Dr. Sheikh A. Akbar, a professor at the university's Department of Materials Science and Engineering, said that further microscopic examinations are warranted to understand better how this process works.
In the tests, Akbar and his team compared cells grown on smooth titanium, smooth titanium dioxide, and the nanowire surface. The greatest increase in cell adhesion and proliferation within the first 15 hours was produced by the cells growing on the nanowires. By the end of the study, the researchers measured about 90,000 cm² on the nanowire surface — 80 percent more than on any of the other surfaces.
The researchers hope that people undergoing a hip or knee replacement, receiving dental implants or with broken bones that require screws or plates will benefit from their discovery in the future. As the technique to grow the wires is fairly simple and cost-effective, they believe that this surface treatment will become a modification to titanium implants that is simple to implement, said Dr. Derek Hansford, co-author of the study and associate professor of biomedical engineering. "A stronger interface with surrounding bone tissue means that implants and bones will be better able to share mechanical loads and we can better preserve healthy bone and soft tissue around the implant site," he concluded.
The study, titled "Thermally Grown TiO2 Nanowires to Improve Cell Growth and Proliferation on Titanium Based Materials," was published in the July issue of the Ceramics International journal.
