Nanotextured Implant Materials: Blending in, Not Fighting Back
Date: 12.4.2007
Texture turns out to be nearly as important as chemistry when designing materials for use in the human body. In two related experiments Brown University engineers Thomas Webster and Karen Haberstroh found that cells responded differently to materials with identical chemistry but different surface textures. On both titanium and polymer materials, nanoscale surface textures yielded a more natural, accepting response, while microscale patterns typical of engineered materials spurred a rejection response.
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Smoother is not better
The faster endothelial cells (green) form a single smooth layer, the less chance exposed metal will provoke an immune response. Samples examined after 1, 3 and 5 days (left to right) show better coverage on nanotextured titanium (bottom row) than on conventional microstructured titanium.
Image: Thomas Webster
Biomedical engineers are constantly coming up with ways to repair the human body, replacing defective and worn out parts with plastic, titanium, and ceramic substitutes – but the body does not always accept such substitutes seamlessly. Engineers from Brown and Purdue universities have found that simply changing the surface texture of implants can dramatically change the way cells colonize a wide variety of materials.
Two recent experiments have focused on the materials used in stents – those springy little cylinders that hold open once-clogged arteries – and artificial blood vessels. Currently only about 30 percent of small diameter blood vessel grafts (less than 6 mm diameter) last more than five years, and up to 20 percent of stents need to be replaced because the artery walls thicken in and around them in a process known as restenosis. Drug-coated stents were introduced years ago as one way to combat this problem, but concerns have surfaced recently about increased clotting....
Whole article "EurekAlert":[ http://www.brown.edu/Administration/News_Bureau/2006-07/06-134.html]
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