Artificial Joints May Soon Run Smoother Sept. 10, 2003 -- A biochemical breakthrough means that replacement joints soon may run a lot more smoothly -- and last a lot longer.

That would be good news for people with artificial hips, knees, and other joints who need expensive surgery when their bionic parts need replacement.

The news comes from the lab of Jacob Klein, PhD, of Israel's Weizmann Institute and England's Oxford University. Klein and colleagues report the finding in the Sept. 11 issue of Nature.

The researchers were studying friction between two surfaces rubbed together under water. To reduce the friction between the surfaces, they attached tiny "bristles" to each surface.

Each bristle is made of long organic molecules with a water-hating bottom half that sticks to the surface. The top half of each bristle is made of water-loving molecules with an electric charge. When two of these "hairbrush" surfaces are rubbed together in water, they repel each other. This makes for minimal friction.

Biological surfaces have similar electrical charges. Klein and colleagues suggest that their polymer brushes may not be new, after all. Mother Nature may already be using them for lubrication.

"Our findings may have implications for ... the design of lubricated surfaces in artificial implants," the researchers suggest.