LOS ANGELES, Feb. 27 (Xinhua) -- A U.S. scientist has produced a wireless sweat sensor that can accurately detect stress levels, a paper revealed on Wednesday.
The sensor can detect levels of cortisol, a natural compound that is commonly thought of as the body's stress hormone, according to the paper appearing in the journal Matter.
The development of an inexpensive and accurate device for measuring cortisol could allow for more widespread and easier monitoring of stress but also of other conditions including anxiety, post-traumatic stress disorder, and depression -- all of which are correlated with changes in cortisol levels.
The sensor developed by Wei Gao, assistant professor of medical engineering at California Institute of Technology, is made of graphene, a sheet-like form of carbon. A plastic sheet is etched with a laser to generate a 3D graphene structure with tiny pores in which sweat can be analyzed.
The sensor was tested in two different ways. In one test, a volunteer's sweat was analyzed over a period of six days, and data representing cortisol levels were collected. In a healthy individual, cortisol levels rise and fall on a daily cycle. The levels peak just after an individual wakes up each morning and decline throughout the day, and that is exactly what the sensor detected.
In the other test, changes in cortisol levels were recorded as they occurred in response to an acute stressor. In the experiments, the sensors detected rising cortisol levels right away.
As Gao is one of six researchers selected by the National Aeronautics and Space Administration (NASA) to participate in studies of the health of humans on deep-space missions, the sensor technology would be potentially applied for monitoring stress and anxiety among astronauts.
"We aim to develop a wearable system that can collect multimodal data, including both vital sign and molecular biomarker information, to obtain the accurate classification for deep space stress and anxiety," Gao said.