Nav: Home

Skin-like sensor maps blood-oxygen levels anywhere in the body

November 07, 2018

Berkeley -- Injuries can't heal without a constant influx of blood's key ingredient -- oxygen.

A new flexible sensor developed by engineers at the University of California, Berkeley, can map blood-oxygen levels over large areas of skin, tissue and organs, potentially giving doctors a new way to monitor healing wounds in real time.

"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."

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.

"All medical applications that use oxygen monitoring could benefit from a wearable sensor," said Ana Claudia Arias, a professor of electrical engineering and computer sciences at UC Berkeley. "Patients with diabetes, respiration diseases and even sleep apnea could use a sensor that could be worn anywhere to monitor blood-oxygen levels 24/7."

Existing oximeters use light-emitting diodes (LEDs) to shine red and near-infrared light through the skin and then detect how much light makes it to the other side. Red, oxygen-rich blood absorbs more infrared light, while darker, oxygen-poor blood absorbs more red light. By looking at the ratio of transmitted light, the sensors can determine how much oxygen is in the blood.

These oximeters only work on areas of the body that are partially transparent, like the fingertips or the earlobes, and can only measure blood-oxygen levels at a single point in the body.

"Thick regions of the body, such as the forehead, arms and legs, barely pass visible or near-infrared light, which makes measuring oxygenation at these locations really challenging," Khan said.

In 2014, Arias and a team of graduate students showed that printed organic LEDs can be used to create thin, flexible oximeters for fingertips or earlobes. Since then, they have pushed their work further, developing a way of measuring oxygenation in tissue using reflected light rather than transmitted light. Combining the two technologies let them create the new wearable sensor that can detect blood-oxygen levels anywhere on the body.

The new sensor is built of an array of alternating red and near-infrared organic LEDs and organic photodiodes printed on a flexible material. The team used the sensor to track the overall blood-oxygen levels on the forehead of a volunteer who breathed air with progressively lower concentrations of oxygen -- similar to going up in altitude -- and found that it matched those using a standard fingertip oximeter. They also used the sensor to map blood-oxygen levels in a three-by-three grid on the forearm of a volunteer wearing a pressure cuff.

"After transplantation, surgeons want to measure that all parts of an organ are getting oxygen," Khan said. "If you have one sensor, you have to move it around to measure oxygenation at different locations. With an array, you can know right away if there is a point that is not healing properly."
-end-
The co-authors on this work are Donggeon Han, Adrien Pierre, Jonathan Ting, Xingchun Wang and Claire M. Lochner of UC Berkeley; and Gianluca Bovo, Nir Yaacobi-Gross, Chris Newsome and Richard Wilson of Cambridge Display Technology Limited.

This work was supported in part by Cambridge Display Technology Limited (CDT, Company Number 2672530) and by Intel Corporation via Semiconductor Research Corporation Grant No. 2014-IN-2571

University of California - Berkeley

Related Electrical Engineering Articles:

Modeling the rhythmic electrical activities of the brain
Researchers studying the brain have long been interested in its neural oscillations, the rhythmic electrical activity that plays an important role in the transmission of information within the brain's neural circuits.
UTA electrical engineering professor earns society's highest honor
J.-C. Chiao, a University of Texas at Arlington electrical engineering professor, has been named a Fellow of SPIE, the international society for optics and photonics.
UTA electrical engineering professor is named an IEEE Fellow
Qilian Liang, a professor in the Electrical Engineering Department at The University of Texas at Arlington, has been named a Fellow of the Institute of Electrical and Electronics Engineers.
HKU Engineering Professor Ron Hui named a Fellow by the UK Royal Academy of Engineering
Professor Ron Hui, Chair Professor of Power Electronics and Philip Wong Wilson Wong Professor of Electrical Engineering at the University of Hong Kong, has been named a Fellow by the Royal Academy of Engineering, UK, one of the most prestigious national academies.
New electrical energy storage material shows its power
A new material developed by Northwestern University chemist William Dichtel and his team could one day speed up the charging process of electric cars and help increase their driving range.
Leaving the electrical grid in the Upper Peninsula
While Michigan's Upper Peninsula is not the sunniest place in the world, solar energy is viable in the region.
Electrical brain stimulation enhances creativity, researchers say
Safe levels of electrical stimulation can enhance your capacity to think more creatively, according to a new study by Georgetown researchers.
Questions over safety of whole body electrical stimulation
It's time to regulate the use of whole body electrical stimulation, argue doctors in The BMJ today, after treating several people for muscle damage at their hospital.
UTA electrical engineering professor elected Fellow of the Royal Society of Chemistry
Samir Iqbal, a University of Texas at Arlington associate professor of electrical engineering at The University of Texas at Arlington, has been named a Fellow of the prestigious Royal Society of Chemistry, the United Kingdom-based association representing more than 50,000 the world's leading chemical scientists.
Using electrical signals to train the heart's muscle cells
Columbia Engineering researchers have shown, for the first time, that electrical stimulation of human heart muscle cells engineered from human stem cells aids their development and function.

Related Electrical Engineering Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".