Diabetics can develop neuropathy — damage to nerves — in their feet, which in turn leads to a loss of sensation. As a result, their feet don’t get sore when pressure is applied to a certain point. In time, this pressure can lead to wounds that are difficult to heal which in turn can result in amputation of toes or even the entire foot. Specialized insoles can help distribute the pressure, custom made by orthopedic shoemakers. The process is expensive and imprecise, as there’s way to evaluate their effectiveness.

Researchers at the Fraunhofer Institutes for Mechanics of Materials (IWM) and for Environmental, Safety, and Energy Technology (UMSICHT) have teamed up to build a better insole for diabetic patients. Using a 3D scan of the patient’s foot, software can print an insole faster and at lower cost than with traditional methods. The actual structure of the insole can be modified as needed to make it stiffer or more flexible. The prototype insoles are currently being tested for flexibility, abrasion resistance, and strength until they fail.

The insoles are printed using a sintering process, in which lasers melt thermoplastic polyurethane (TPU) material to create successive layers. In time, this new process could provide diabetes patients with custom-built insoles faster and at a lower cost, which in turn could help improve their health outcomes and avoid the expensive treatment of complications that can result from neuropathy.