Expressive Bandage Displays Infectious Spread

Infections are often worse than the initial wound, spreading and worsening beneath old bandages soaked through with drying fluids. With the addition of an indicator dye developed by the Fraunhofer Institute in Germany, those fetid wraps can know speak for themselves, indicating when an infection has taken root and a dressing needs changing.

Scientists at the Fraunhofer Research Institution for Modular Solid State Technologies EMFT in Munich have developed dressing materials and plasters which indicate pathological changes in the skin. If an infection is present, the color of the dressing changes from yellow to purple.

“We have developed an indicator dye which reacts to different pH values, and we have integrated it into a dressing and a plaster. Healthy skin and healed wounds usually show a pH value of below 5. If this value increases, it is shifting from the acid to the alkaline range, which indicates complications in the healing of the wound. If the pH value is between 6.5 und 8.5 an infection is frequently present and the indicator color strip turns purple,” states Sabine Trupp, scientist at Fraunhofer. In this way the intelligent dressing material makes it possible to regularly check wounds from the outside without disrupting the healing process.

A prototype of the dressing has already been produced and initial tests have proved successful. The researchers are now considering how to develop their innovation further. There are plans to integrate optical sensor modules into the dressing to measure the pH value and indicate the results on a reader unit. This method would allow the value to be read off precisely, providing information about how the wound is healing.