Monitoring how serious wounds are healing can be a challenging endeavour, the wound usually being hidden from view by bandages. Beside visual assessment, the oxygenation of wound tissue is an important parameter that would provide a lot of information to clinicians. Now a new paint-on bandage developed at Harvard can provide both a window to see the wound and indication of the oxygen saturation below the bandage.
The bandage consists of phosphorescent molecules that are covered by a paint-on transparent flexible material. When light is shined onto the bandage, the phosphor molecules are activated and continue glowing after the light is turned off. The less oxygen is present around the molecules, the longer they glow. Using a smartphone as a sensor to time how long the bandage glows for indicates the amount of oxygen in the wound.
Immediate applications for the oxygen-sensing bandage 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.
“The need for a reliable, accurate and easy-to-use method of rapid assessment of blood flow to the skin for patients remains a clinical necessity,” said co-author Samuel Lin, an HMS associate professor of surgery at Beth Israel Deaconess Medical Center. “Plastic surgeons continuously monitor the state of blood flow to the skin, so the liquid-bandage oxygenation sensor is an exciting step toward improving patient care within the realm of vascular blood flow examination of the skin.”
What’s the next step for the bandage? “We’re developing brighter sensor molecules to improve the bandage’s oxygen sensing efficiency,” said Emmanuel Roussakis, another research fellow in Evans’ laboratory and co-author, who is leading the sensor development effort. The team’s laboratory research will also focus on expanding the sensing capability of the bandage to other treatment-related parameters—such as pH, bacterial load, oxidative states and specific disease markers—and incorporating an on-demand drug release capacity.
“In the future, our goal for the bandage is to incorporate therapeutic release capabilities that allow for on-demand drug administration at a desired location,” says Evans. “It allows for the visual assessment of the wound bed, so treatment-related wound parameters are readily accessible without the need for bandage removal—preventing unnecessary wound disruption and reducing the chance for bacterial infection.”
Study in Biomedical Optics Express: Non-invasive transdermal two-dimensional mapping of cutaneous oxygenation with a rapid-drying liquid bandage…
Press release: ‘Smart’ Bandage Emits Phosphorescent Glow for Healing Below…