When a person's skin is burnt or otherwise injured, part of the body's healing process involves boosting oxygen levels in the damaged tissue. If doctors treating such injuries know how high those levels are, then they can determine how quickly and thoroughly the skin is healing. In order to help them obtain that information without having to remove the wound dressing, an international team of scientists has created a glowing paint-on bandage.
The application process begins with a viscous fluid being applied directly onto the wound. This fluid contains phosphors and a reference dye, and it dries into a thin film within about one minute. A transparent "barrier" fluid is then painted over top of that film. When it dries and seals against the skin, it keeps the underlying film from coming into contact with oxygen in the air. This means that the only oxygen to which it's exposed is coming from the patient's body tissue.
When caregivers subsequently want to check on how the wound is healing, they use a hand-held imaging device to emit a flash of light to the area. The phosphors in the film absorb that light and then instantaneously re-emit it. The lower the oxygen levels are within the tissue, the longer and brighter the phosphors glow.
Although not visible to the naked eye, that fluorescence can easily be imaged using a smartphone or basic camera. Additionally, the color-changing dye in the film provides users with a graduated red-to-green color map, which indicates the distribution of oxygen levels throughout the wound site.
The research is being led by Assistant Professor Conor L. Evans at the Wellman Center for Photomedicine of Massachusetts General Hospital and Harvard Medical School.
In the near future, the bandage's applications could include "monitoring patients with a risk of developing ischemic (restricted blood supply) conditions, postoperative monitoring of skin grafts or flaps, and burn-depth determination as a guide for surgical debridement – the removal of dead or damaged tissue from the body."
Down the road, the bandage may additionally be able to monitor things like pH, bacterial levels and disease markers, plus it could release medication into the wound site on demand. A paper on the research was recently published in the journal Biomedical Optics Express.
A team at the University of Bath has also developed a "smart" wound dressing, that changes color to indicate bacterial infections.
Source: The Optical Society
