Branching polymer could heal cataract wounds

Cataract surgery might get a little easier thanks to a transparent gel that seals surgical incisions in the eye better than standard sutures do.

Approximately 11 million patients worldwide undergo cataract surgery each year. In the procedure, surgeons make a small incision in the cornea, remove the clouded lens, replace it with a clear synthetic lens, and close the incision with nylon sutures. These sutures sometimes cause inflammation and infections.

Mark Grinstaff of Boston University has devised an alternative to nylon sutures. He combined two types of polymers to make a gel that’s biocompatible and degradable. One of the ingredients is a large, branched molecule called a dendron, and the other is a linear polymer. When mixed, the linear polymer stitches together the dendron’s branches, forming a gel.

Working with their colleagues of Duke University Medical Center in Durham, N.C., Grinstaff’s team tested the material on an eye from a cadaver. They sealed a small incision in the eye’s cornea with the gel or closed it with nylon sutures. The gel withstood eye pressures several times greater than the sutures did. That suggests the gel could be better than sutures at healing incisions while keeping inflammation and infection in check. Grinstaff says that tests on patients could begin in 3 to 4 years, after additional laboratory and animal studies are completed.

The researchers report their findings in the Oct. 13 Journal of the American Chemical Society.