Researchers created a flexible skin sensor that maps blood-oxygen levels over large areas of skin, tissue, and organs using organic light-emitting diodes (OLEDs), to provide doctors with a way to monitor healing wounds in real-time.
The sensor is made of organic electronics printed on bendable plastic that conforms to the body’s contours. It can detect blood-oxygen levels at nine points on a grid, unlike fingertip oximeters, and can be placed anywhere on the skin. According to the researchers, it could map the oxygenation of skin grafts or look through the skin for monitoring oxygen levels in transplanted organs.
Existing oximeters only work on partially transparent areas of the body, such as the fingertips or earlobes. Researchers took their work a step further by developing a method of measuring oxygenation in tissue using reflected light rather than transmitted light.
An array of alternating red and near-IR OLEDs and organic photodiodes printed on a flexible material makes up the skin sensor. They used the sensor to track the overall blood-oxygen levels on the forehead of a volunteer who breathed air with progressively lower oxygen concentrations and discovered that they matched those measured with a standard fingertip oximeter.