Pressure-Responsive Fibers Could Lead to Color-Changing Bandages

Engineers at MIT have developed photonic fibers that change color in response to pressure. The innovation could lead to color-changing bandages that allow clinicians to easily know if they’re tight enough or too tight.

Compression stockings and bandages are a common treatment for venous ulcers. However, it can be difficult to tell if an optimal level of pressure is being applied by a bandage. “Getting the pressure right is critical in treating many medical conditions including venous ulcers, which affect several hundred thousand patients in the U.S. each year,” said Mathias Kolle, a researcher involved in the study.

The MIT researchers have as their ultimate goal the development of a pressure bandage that a doctor can easily apply to the correct pressure, and then easily monitor to see if it maintains that pressure over time. Their proposed solution involves a dressing that would change color under pressure, so a doctor could check the color against a chart and determine if the bandage is at the correct pressure.

To achieve this, the research team proposes to use a dressing threaded with photonic fibers. They have developed the fibers using transparent rubber, that they roll into layers, like those in a jelly roll. The fibers are ten times thicker than a human hair and reflect light at the interface between the thin layers.

Reflections at different layers interact with each other to reinforce some colors in the visible spectrum, resulting in different vibrant colors depending on the thickness of the layers. The same principle is at work in the colors that are visible in soap bubbles and in the colorful swirls visible in oily puddles.

The team incorporated the pressure-sensitive fibers into pressure bandages and tested them on student volunteers. Applying the bandages to each other, the students compared them with conventional bandages. With the help of a color chart, they were able to more easily apply the color-changing bandages with an optimal level of pressure, compared with the conventional bandages.

At present, the researchers are working on ways to scale up their production of the fibers, so that they can be produced more cheaply.

Study in Advanced Healthcare Materials: Stretchable Optomechanical Fiber Sensors for Pressure Determination in Compressive Medical Textiles…

Via: MIT…