The key to reconstructing a face is restoring the underlying bone structure. Our facial bones largely determine our appearance, which is why forensic artists can build lifelike busts from nothing more than a skull.

Today, surgeons who are trying to reconstruct the face generally rely on the materials at hand. To build the jaw, for example, they may harvest bones from elsewhere in a patient’s body, often a fibula—the thinner of two bones in the lower leg. They break the fibula into four pieces, chisel them to fit, and rearrange them to rebuild the jaw. While the approach is considered state-of-the-art, Grayson calls it a “stopgap.”

“It’s a little like MacGyver, right?” the 40-year-old engineer says, over a cup of coffee at Balducci’s Cafe in the Johns Hopkins Hospital’s Sheikh Zayed Tower. He is referring to the fictional 1980s TV character who could make anything using only a Swiss Army Knife and whatever came to hand. “There are not a lot of good options for people who have had craniofacial deformities,” Grayson concludes.

As a postdoc at Columbia University, Grayson developed a process that for the first time grew a precisely shaped piece of human jaw bone outside the body. He did this by creating a machine-milled, jaw-shaped scaffold made of bone from cows’ knees, coating it with human stem cells, and then incubating it in a small, boxy device called a bioreactor, which fed nutrients and oxygen to the stem cells while molding the fresh bone to the proper shape.

His paper on the work created a lot of excitement among tissue engineers and was featured in The New York Times and Scientific American, and the biotech startup EpiBone was launched to commercialize this work. The small company was one of 49 worldwide invited to the 2016 World Economic Forum in Davos, Switzerland, in January.

In the Biomedical Engineering Department, Grayson plans to speed up adoption of his approach to facial regeneration by streamlining the process. He hopes to eliminate the bioreactor and use 3-D printers to produce custom-designed, porous, biodegradable plastic scaffolds in the shape of the required bone that can be implanted directly in the face.

The whole procedure might take just six to 12 hours, compared to the five weeks required to incubate new bone outside the body. And it would help the body start work immediately on absorbing, integrating, and replacing the implant.