Injectable Biomaterials

Surgically repairing delicate soft tissues like those on the face after an injury or illness is a tricky business. Surgeons can fix bones, joints and other body parts--but lips and cheeks simply aren't as repairable. But they soon may be, if a new material developed by medical researchers becomes commercially available. The Johns Hopkins team has come up with an injectable smart material that lets surgeons "sculpt" fine features into the tissue's shape, and then fix them in place with a simple burst of LED light.

The material is a mixture of hyaluronic acid and polyethylene glycol. The acid is already approved for use as a soft-tissue implant, and glycol, or "PEG" as it's known, is a material that has uses in manufacturing, the beauty industry, and medicine. When blended, the two liquids create a biomaterial--partly synthetic, partly biological--that's a polymer, one that's fluid enough to be injected.

Surgeons would inject the biomaterial into the skin and massage the features into the desired shape. By exposing the material to bright-green LED light (bright enough to penetrate skin up to four millimeters thick), the polymer molecules change their properties and tangle to form a rigid structure, setting the shape of the implant permanently.

This means big changes for patients suffering from facial disfiguration, a highly visible injury that can have social consequences. But that's just the most obvious use. If the material becomes a commercial product, we could see a wealth of potential customers among the extreme body-modification set. After all, the idea of reliably adding semi-permanent Klingon-like bumps to your face with a simple injection (a far less risky and expensive process, perhaps, than full-on plastic surgery) will definitely interest some people.

It's been tested on rats, and in a very limited form on humans too, with very positive results and only minor side effects. A full-scale human test is upcoming, and the only issue so far is that the material degrades at a rate that could mean re-injections are needed every year or so--but the team thinks new tissue may actually grow into the implants in time.