Purdue University researchers have developed a shoe insole that could help make the healing process more portable for the 15 percent of Americans who develop ulcers as a result of diabetes. The researchers used lasers to shape silicone-based rubber into insoles, and then created reservoirs that release oxygen only at the part of the foot where the ulcer is located.

“One of the ways to heal these wounds is by giving them oxygen,” said Babak Ziaie, PhD, a professor of electrical and computer engineering at the university. “We’ve created a system that gradually releases oxygen throughout the day so that a patient can have more mobility.”

According to the team’s simulations, the insole can deliver oxygen at least eight hours a day under the pressure of someone weighing about 53-81kg (117-179 lb.) but can be customized to any weight.

“Silicone is flexible and has good oxygen permeability,” said Hongjie Jiang, PhD, a postdoctoral researcher in electrical and computer engineering. “Laser machining helps us to tune that permeability and target just the wound site, which is hypoxic, rather than poison the rest of the foot with too much oxygen.”

Next, the researchers want to create a way to 3D print the whole insole, rather than printing a mold first and then laser-machining a pattern. They also plan to test the insole on actual diabetic ulcers to further gauge how well the insoles advance the healing process.

The team envisions low-cost mass customization wherein a manufacturer could fill a prescription for a pack of pre-filled insoles customized to the patient’s wound site.

The team published its work in the September issue of the Materials Research Society Communications.

This story was adapted from materials provided by Purdue University.