When potters join two pieces of clay, they rough the surfaces to create a stronger bond. It turns out that bones work the same way: Ohio State University researchers found that when they covered a metal implant in tiny wires, bone material grew on it up to 80 percent faster than smooth surfaces.
The wires could coat plates and screws meant to speed recovery from a broken bone or help a joint replacement bond with the surrounding skeleton. To test how to best promote cell growth, researchers grew metal nanowires tens of thousands of times smaller than a human hair on a titanium surface and combined them with cancerous bone cells. They also exposed smooth titanium surfaces to the cells.
In the first 15 hours, cells that attached to the wire-covered surface released a 20 percent higher concentration of molecules that promote further cell growth. By the end of the study, there were 90,000 cells per square centimeter on the wire surface, compared to 50,000 on the smooth surfaces.
“Our hope is that this surface treatment will become a simple-to-implement modification to titanium implants to help them form a stronger interface with surrounding bone tissue. A stronger interface 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,” study co-author Derek Hansford said in a release.
The researchers say it’s very simple to grow the wires, which are made by combining materials and gases in a furnace. At around 1,300 degrees, the wires emerge from a smooth titanium surface. Then they grow an aluminum coating. The researchers don’t know how the coating forms, as the wires are made of titanium.
“It’s strange that we don’t completely understand why this process works the way it does. We’re going to have to do some fancy microscopy to figure it out, but we do know that the wires only form under just the right conditions,” team lead Sheikh Akbar said.