Surface changes

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.

Now, engineers from Brown and Purdue universities have found that simply changing the surface texture of implants can dramatically change the way cells colonise 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.