For years, University of Washington bioengineer Buddy Ratner has used the metaphor of a lock and key to describe how the body uses specific cell-protein interactions to promote healing. Now, research suggests that the metaphor offers a nifty blueprint for making medical implants that trigger normal healing rather than the body's typical, and often disruptive, foreign material reaction to such devices.
Reporting in the April 15 issue of Nature, Ratner and UW bioengineering graduate student Galen Shi describe a technique they developed for coating a biomaterial surface with tiny keyhole-like indentions that bind specific proteins to potentially unlock the body's natural healing process.
"The ability to make surfaces that can be recognized by the body is a major step forward in our quest for biomaterials and implants that heal," says Ratner, who directs the UW Engineered Biomaterials Center, a $25 million National Science Foundation initiative to create next-generation medical implants. "This is the first coating process that works on the atomically flat surfaces of artificial materials commonly used in implants and that promotes affinity for specific proteins. Our approach potentially can be used for any kind of implant." (See end of release for information on downloading a publication quality image of Professor Ratner and an illustration of the UW coating process.)
More than a half billion medical devices, ranging from simple catheters to heart valves and artificial hips, are implanted in patients every year. While these devices save or improve the lives of millions of people, they often deliver only temporary fixes. The body's natural response to foreign material - whether it's a medical implant or a bullet - is to wall it off with scar-like tissue, Ratner explains. Frequently, this reaction disrupts the device's performance and necessitates further medical intervention.