Researchers at the Fraunhofer Institute for Silicate Research ISC in Würzburg, Germany have developed a pressure-monitoring stocking to help protect against wounds using an integrated sensor system. The stocking includes 40 very fine, dielectric elastometer sensors to measure compression loan and distribution for patients with diabetes.
“Existing systems on the market measure the pressure distribution only on the bottom of the foot using shoe inserts. Our sensors are attached to the stocking’s sole, at the heel, the top of the foot and the ankle, so they can take readings in three dimensions,” Bernhard Brunner, PhD, Fraunhofer ISC research scientist, stated in a press release.
The stocking’s sensors are made from a soft, stretchy elastomer silicone coated on both sides with highly flexible electrodes of graphite or carbon black. When the film deforms as a result of compression or stretching, its thickness decreases and its surface area simultaneously increases. This means its capacitance increases with pressure – an effect the ISC researchers can measure. For example, if a patient stands for an extended period in one spot, pressure will build. The sensors can recognize this, and transmit the measurement signal via a conductive thread to a wireless electronics unit developed by researchers at Fraunhofer IIS and consisting of an application-specific integrated circuit (ASIC) chip and a controller.
The ASIC collects the measurement data and the controller transmits it wirelessly to a smartphone or tablet, which then informs the stocking wearer that it is time to change foot position or weight distribution. The researchers have filed a patent application for the stockings.