SAN DIEGO, Calif. – What if, with one big breath, you could determine your liver function or glucose levels? Researchers at the State University of New York, Stony Brook have developed a diagnostic breathalyzer that will make connotations with blood alcohol content a thing of the past.
"There are over 1,000 chemical compounds [in our breath] that are in very, very low concentrations. We capture breath, detect a specific gas biomarker, then quantify its concentration," said Perena Gouma, professor and director of Stony Brook's Materials Science and Engineering department. "We developed a sensor chip coated with tiny nanowires that detect minute amounts of chemical compounds in the breath," she said.
Perena Gouma watches as a student demonstrates the breathalyzer.
(Source: National Science Foundation)
Nanowires in Gouma's crystallo-chemical sensor are attuned to specific chemicals -- nitric oxide, carbon monoxide, carbon dioxide, ammonia, acetone, isoprene, benzene, ethane, and pentane -- and measure concentration by the amount of particles that get caught in the wires. Those particles become data, which correlates with various diseases. One 100 micrometer crystalline nanowire has a surface area and gas sensitivity 100 times greater than a silicon-based polycrystalline film, and its electrospun array mimics a nose.
Nanowires catch particulate chemical compounds.
(Source: SUNY Stony Brook)
For example, the presence of ethane and pentane in concentrations beyond 1-11 parts per billion (ppb) is an indicator of oxidative stress. A reading of ammonia levels beyond 200-1750 ppb could mean kidney failure. Gouma said isoprene monitoring could find applications in defense, identifying fatigue and sleep apnea among soldiers.
"You could do hemodialysis monitoring. Those suffering from renal failure have elevated amounts of ammonia in their breath," Gouma noted, adding that dialysis is typically a one-time-fits-all treatment.
Part of the breathalyzer's success is due to published guidelines on nitric oxide concentrations in breath. At the TSensors Summit, held here, Gouma called for more support from the medical community to develop breath biomarkers.
The breath analyzer will likely find fame as a metabolic rate monitor, Gouma said. The device could measure acetone in breath for diet control, which could lead to diabetes monitoring. The average concentration of acetone in breath from a non-diabetic is less than 0.8 parts per million (ppm), while type-1 diabetics show greater than 1.8 ppm levels.
"If this is successful, it will guide the way toward diabetes monitoring. There is a better correlation between acetone and insulin levels than glucose and insulin levels," she said.
TSensors Summit Chair and CEO Janusz Bryzek spoke to the increasing need for non-invasive diabetes care, calling glucose monitoring “the holy grail” of sensor work. Acetone, however, may be the new player to beat in the quest for diabetes devices.
— Jessica Lipsky, Associate Editor, EE Times