Older joggers use oxygen as efficiently as young runners, study.
Measuring the oxygen content in blood when exercising helps joggers and their doctors keep track of health parameters. REUTERS

Blood-oxygen levels could be added to the list of vital signs tracked by cheap, wearable medical health trackers soon.

Pulse oximeters available in the market do measure pulse rate and blood-oxygen saturation levels, but being part of rigid conventional electronics are not wearable, unlike those that Berkeley scientists promise.

Engineers at UC Berkeley are developing a new organic, optoelectronic sensor that is thin, cheap and flexible enough to be slapped on like a Band-Aid, says a UCB press release.

Accurate pulse and oxygen readings are reported in the findings published in Nature Communications.

Conventional pulse oximeters that work with Silicon as base material use light-emitting diodes to send red and infrared light through a fingertip or earlobe they are attached to.

Sensors detect how much light makes it through to the other side.

Oxygen-rich blood absorbs more infrared light, while the darker hues of oxygen-poor blood absorb more red light. The ratio of the two wavelengths reveals how much oxygen is in the blood.

The organic sensors used by UCB use red and green light, which are able to distinguish high and low levels of oxygen in the blood even better than red and infrared light.

"We showed that if you take measurements with different wavelengths, it works, and if you use unconventional semiconductors, it works," said Ana Arias, an associate professor of electrical engineering and computer sciences and head of the UC Berkeley team that is developing the new organic optoelectronic sensor. "Because organic electronics are flexible, they can easily conform to the body."

The organic sensors are so cheap that they can be disposed after use and do not need to be disinfected for contamination like conventional rigid sensors.