‘Nanotextured’ materials eyed for better implants

The tiny springy cylinders that hold open once-clogged blood arteries may soon be getting safer and more effective.
Researchers at Brown University and Purdue University who are working with a nanotechnology company in Indiana recently reported that they have developed a promising new way to make medical implants that can be more easily accepted by the body.
The vascular stents and artificial arteries now used by doctors are laden with chemicals to reduce the thickening of the artery walls that occurs as the body responds to foreign intrusion. But those chemicals are also toxic to the vascular cells themselves, so most of those grafts and implants ultimately need to be replaced. Today, only 30 percent of small blood-vessel grafts last more than five years, according to a Brown news release.
Blood vessels have a thin lining of specialized cells called the endothelium, surrounded by a thicker layer of smooth muscle cells that make up the arterial wall. Proteins make up much of this lining and create a texture of tiny bumps on the inside of the blood vessel. This contrasts with most of the materials used in artificial blood arteries and implants, which have micro-scale texture, but are nearly smooth on a microscopic scale.
The researchers changed the surface texture of implant materials to form miniature bumps, allowing endothelial cells to quickly colonize the foreign surfaces, camouflaging them and preventing plaque cells from overgrowing the implants.
Thomas Webster, an associate professor of engineering at Brown working on the project, said the technology’s biggest impact could be on vascular stents.
“What we’re trying to do is fundamentally different,” he said. “We’re trying to find materials that the body accepts, rather than develop drugs or develop materials that will kill a cell – no matter if it kills a bad cell or a good cell. We’re trying to find materials that accept good cells, as opposed to killing off bad cells.”
At Brown, Webster is working with Karen Haberstroh, an assistant professor of engineering, to bring the new nanotechnology to hospitals within five years. This fall the research team will begin a six-month animal testing procedure and will then partner with the Indiana company NANO VIS to start human trials.