New wound dressing changes color when infections occur

Scientists in Germany have created new wound dressing materials that change from yellow to purple in color when an infection develops.

The new material will allow caregivers to check on wounds without removing dressings, a practice that can delay healing. Residents also should experience the pain of dressing removal less often.

Researchers’ breakthrough is an indicator dye that is integrated into the dressing. The dye is sensitive to changing pH values and turns purple when an infection is present in a covered wound.

“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 and 8.5, an infection is frequently present and the indicator color strip turns purple,” said Sabine Trupp, Ph.D., a researcher at the Fraunhofer Research Institution for Modular Solid State Technologies in Munich.

Production of the color-control strip posed a number of challenges for the research scientists since it had to meet several different requirements: “The dye has to remain chemically stable when bonded to the fibers of the dressing material to ensure that it does not get into the wound. At the same time, the indicator must show a clear change in color and also react sensitively in the right pH range,” Trupp explained.