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Sci-Tech

Paint-on bandage changes color as your wound heals

A smart liquid bandage glows to reveal the amount of oxygen the wound underneath is getting, and that could help doctors help us heal.

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Looks like this guy could really benefit from the new "S.M.A.R.T" bandage.taymtaym/Flickr

As humans, we sure do love our oxygen. So it naturally follows that our wounds crave the stuff as well. Oxygen is a critical component of the healing process, whether our wounds result from a burn, cut or tissue transplant. Until now, however, monitoring wounds meant removing bandages to observe their progress, potentially aggravating the vulnerable areas and exposing them to harmful bacteria.

An international team of researchers led by Professor Conor L. Evans at the Wellman Center for Photomedicine of Massachusetts General Hospital and Harvard Medical School, has come up with a unique "paint on" bandage that would eliminate the need to remove it to check oxygen levels. The bandage is impregnated with phosphors -- chemicals that absorb light and then release it by glowing (think glow-in-the-dark watch). The phosphors are designed in such a way that they glow red when a wound isn't getting enough oxygen, and green when it is.

The glowing effect of the bandage is triggered by a light source the researchers have also developed, which they say can be captured using the camera on a smartphone. They are hopeful that a field-ready model of the system will be ready soon.

In addition to indicating the rate at which a wound is getting oxygen, Evans told CNET the bandage is particularly valuable because it can also map the oxygen supply across a wound. So if there is a loss of oxygen at any one part of the wound, doctors would be able to focus their attention in that area.

Evans said that the bandage could truly "shine" in three arenas in particular. The first would be helping with chronic wounds such as those suffered by diabetics. These, he says, cost the health care system an estimated $25 billion per year.

"Oxygenation is also crucial for burns, especially when the burn is 'debrided' to remove dead tissue and encourage healing," he added. "Without an accurate assessment of oxygenation, clinicians can over- or under-debride, resulting in poor functional and cosmetic consequences.

"Another area of wound care where oxygen is critical is in the care of tissue transplants; when tissue are grafted, they require oxygen supply at their new site to survive. Transplanted tissues with poor blood and oxygen supply undergo cellular death. There are many ways a graft can lose its oxygen supply, from anastamotic failure (rupture of the sutured arteries) to venous congestion (clogs in the draining veins), so it is important to have a simple, visual assessment of oxygenation in grafted tissues in case these complications occur."

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Mapping our wounds. Li/Wellman Center for Photomedicine

Currently, the researchers are working to improve the wound covering, which they call a S.M.A.R.T bandage (sensing, monitoring and release of therapeutics). They are developing more powerful phosphors to improve its oxygen-sensing function. They are also working to develop a bandage that could pick up on more parameters than just oxygen such as pH and bacteria levels. Finally, they're investigating ways in which the bandage could automatically deliver drugs at the wound site.

News of the smart bandage was published last week in The Optical Society's (OSA) open-access journal, Biomedical Optics Express.