Engineering Minute

Engineering Minute – Flexible, large-scale oximeter

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A group of engineers at University of California, Berkeley have developed a flexible sensor composed of LED lights that can measure blood-oxygen levels over a large surface area. The sensor can be used on both skin and organs, giving doctors a novel way of monitoring healing wounds in real time.

flexible large-scale oximeter on a patient's arm
A new sensor made of an alternating array of printed light-emitting diodes and photodetectors can detect blood-oxygen levels anywhere in the body. The sensor shines red and infrared light into the skin and detects the ratio of light that is reflected back. (UC Berkeley photo by Yasser Khan, Arias Research Group)

“When you hear the word oximeter, the name for blood-oxygen sensors, rigid and bulky finger-clip sensors come into your mind,” said Yasser Khan, a graduate student in electrical engineering and computer sciences at UC Berkeley. “We wanted to break away from that, and show oximeters can be lightweight, thin and flexible.”

 

From the University of California, Berkley article: "The sensor, described this week in the journal Proceedings of the National Academy of Sciences, is made of organic electronics printed on bendable plastic that molds to the contours of the body. Unlike fingertip oximeters, it can detect blood-oxygen levels at nine points in a grid and can be placed anywhere on the skin. It could potentially be used to map oxygenation of skin grafts, or to look through the skin to monitor oxygen levels in transplanted organs, the researchers say."

 

Current oximeters work on measuring transmitted light and therefore can only work on areas of the body that are partially transparent such as the fingertip or earlobe. The new sensor is built from an array of near-infrared and red LEDS and photodiodes that are printed on a flexible material. This allows it to work with reflected light and can be used on denser body parts such as a person's forehead or forearm.

 

Read more about the flexible, large-scale oximeter at University of California, Berkeley