Sweat can be a smelly messenger, but one that also carries a trove of valuable information about how our bodies are feeling. Scientists at several labs are now trying to pick its lock with nanotechnology, including know-how transferred from GE’s jet engine research, to develop flexible, Band-Aid-like wireless sensors sensitive enough to detect a drop of biomolecules found in sweat in 2.5 million gallons of water.
“We are developing small wireless sensors for measuring biological markers in sweat that affect our stress and energy levels,” says Scott Miller, lab manager for nanostructures and surfaces at GE Global Research. “We can do it with a blood test, but we would like to detect the early signs of stress and fatigue non-invasively from sweat. The faster we can spot it, the earlier we can deal with it.”
Miller and his team are working with the University of Massachusetts Amherst and the University of Cincinnati on the project, which is partially funded by the Nano-Bio Manufacturing Consortium (NBMC) and the U.S. Air Force.
The body has two types of sweat glands, eccrine and appocrine. It’s the appocrine glands, which are located in areas like the armpits and the groin, that are active during stressful situations and produce thicker, oil-like perspiration. Body odor comes from bacteria feasting on this kind of sweat. Top Image Credit: Val Gempis, U.S. Air Force.
Nanotechnology can manipulate matter on the level of atoms and molecules. “That’s why our receptors are so sensitive,” says materials scientist Azar Alizadeh, who is on Miller’s team.
The receptors inside the sensors attract the biomarkers and convert them into electrical signals. The signals then travel wirelessly to a database for storage and analysis. “We’re actually utilizing expertise in microfluidics that we typically apply to manipulate and improve the airflow and efficiency of our aircraft engines to direct the sweat over the sensor ever so precisely,” Alizadeh wrote on her blog. “We create pathways and valves in the sensor itself to control where the sweat goes, so that we can get the most accurate measurement.”
The target biomarkers include Orexin-A, which is a naturally occurring neuropeptide hormone released by the hypothalamus in the brain. It plays a crucial role in the stability of arousal and alertness. Another target is the stress hormone cortisol. “Cortisol level changes during the day, but with this device, we will have a dynamic reading,” Alizadeh says. “We could see in real time how your body responds to stress.”
The Air Force is interested in using the sensors to monitor pilots and understand and improve their performance. But the technology could have much broader civilian applications. “Physical and mental fatigue is a factor for air traffic controllers, fire fighters, heavy-equipment operators, and many other professions,” Miller says.
The tiny sensors could also go big in healthcare. “One day we could be analyzing electrolytes, metabolites and other molecular markers correlated with disease,” Miller says. “We’re already doing this with patient monitors in the hospital, but this technology will cut the wires.”