Smart insole for diabetic foot monitoring

Foot ulcer is a severe complication affecting about 25% of diabetes mellitus patients due to a lower blood supply and loss of foot sensitivity (neuropathy). A fast and reliable identification of foot pressure loads and temperature distributions changes on the plantar surface allows to prevent and reduce the consequences of ulceration such as foot or leg amputation. Several wearable technologies have been developed and tested by the scientific community, addressing the "diabetic foot" topic. However, the dimensions of the devices and the combined pressure/temperature monitoring capabilities don't accommodate the requirements from both the end-users and caregivers: normally just one information--pressure loads or temperature map--is acquired, moreover the amount of thermal reading points is lower than 5 and the accuracy of thermal sensors is greater than 0.5 °C. This work presents a smart insole in which both temperature and pressure data in 8 reading points are monitored in remote way for the assessment of the health foot conditions by a caregiver. Minimally invasive and low power temperature and force sensors have been chosen and integrated into two antibacterial polyurethane-based layers architecture, designed in accordance with the typical requirements of diabetic foot. Based on the results, the developed system shows high performance in terms of temperature and pressure detection.