Purdue University researchers have developed a shoe insole that could help make the healing process more portable for people who have diabetes-related foot ulcers. The researchers used lasers to shape silicone-based rubber into insoles and then create reservoirs that gradually release oxygen throughout the day. The reservoirs are strategically placed to allow the oxygen to target just the wound site, which is hypoxic, rather than poison the rest of the foot with too much oxygen.
The current gold standard for treating an ulcer is a total-contact cast. The challenge is, no one knows what’s happening inside that cast. “If we could test how well this insole delivers oxygen to the wound site from within the cast, then this could be a way of aiding the healing process,” explained Desmond Bell, DPM, a podiatrist in wound management and amputation prevention at Memorial Hospital, Jacksonville, FL, and founder of the Save a Leg, Save a Life Foundation.
Simulations to date show the insole can deliver oxygen at least 8 hours per day under the pressure of someone weighing about 117–179 pounds. Researchers believe the insole can be customized to any weight. The team envisions a manufacturer sending a patient a pack of pre-filled insoles customized to his or her wound site, based on a wound profile obtained from a physician’s prescription and a picture of the foot.
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 patients with diabetic foot ulcers to further gauge how well the insoles advance the healing process.