A new high-tech bandage will glow brightly to tell doctors if a wound is not healing.The bandage turns fluorescent green if conditions inside wounds are hampering the healing process. The colour changes are brought on by a drop in levels of oxygen inside the wound.Severe wounds, ulcers and burns need a sufficient supply of oxygen to stimulate the growth of healthy new tissue. Blood vessels in the skin bring oxygen to the wound, but often these are damaged, too, which limits blood flow or the oxygen demand of the healing cells outstrips supply.Once a wound has been covered by a conventional bandage, it is difficult for doctors to assess how well it is healing without repeatedly changing dressings, which can be painful for the patient and increases the risk of infection.Though there are probe-like devices that can measure the levels of oxygen in damaged tissue, they still require access to the open wound. Around 200,000 patients in Britain have a chronic wound that needs constant care, and the annual cost to the NHS is estimated at £3 billion.In many cases, the wounds are due to ulcerations to the lower leg caused by damage to the circulation from diabetes.Scientists at Massachusetts General Hospital and Harvard Medical School, in Boston, U.S., set out to develop a revolutionary bandage that could tell doctors and nurses if healing is underway. Around 200,000 patients in Britain have a chronic wound that needs constant care If it is not, the patient may need surgery to remove some of the decomposing tissue, in order to improve the chances of healthy new tissue forming. The new bandage contains phosphors, the tiny molecules that are used to make phosphorescent paint, and which are found in everything from glow-in-the-dark watch dials to T-shirt lettering. Phosphors work by absorbing light, storing it and then releasing it gradually over a long period. The phosphor molecules in the bandage respond to changes in oxygen levels. If levels are stable, the bandage remains translucent. However, a lack of oxygen means the phosphor molecules have more energy, and they begin to glow. The lower the oxygen levels, the brighter the molecules shine. The new bandage is applied in the form of a liquid that contains thousands of these molecules.The liquid dries to a solid film in less than a minute and forms an airtight seal.The high-tech bandage has yet to undergo large-scale testing and is unlikely to be available for at least two to three years. But the hope is that, as well as chronic wounds, the bandage could also be used to monitor healing of skin grafts and burns. Commenting on the trial, Professor David Leaper, visiting professor of wound healing at Cardiff University and Imperial College London, said: 'An oxygen-sensing bandage is a great idea for the management of leg ulcers.'There is technology available to measure oxygen, but it involves cumbersome and expensive equipment. This new innovation sounds like a great idea, but I would like to see it in practice.'n MEANWHILE, scientists are giving patients small electric shocks in an effort to tackle hard-to-heal wounds. A new device delivers small electric shocks via electrodes stuck on various points on the legs to trigger regular, small muscle contractions. Previous research has shown muscle contractions stimulate blood flow to the leg, which boosts healing. Muscles are stimulated by walking around, but severe ulcers may limit mobility. This device could provide a solution. It is being tested on 50 patients at Mid Western Regional Hospital, Ireland. source
