A sensor developed at the University of Pittsburgh could strip the element of surprise from some asthma attacks by detecting one before its onset. Fitted in a hand-held device, the tiny sensor could provide people who have asthma with a simple and affordable means of keeping tabs on their condition by measuring their breath for high levels of a specific gas associated with asthma inflammation.
Researchers led by Alexander Star, PhD, a chemistry professor in Pitt's School of Arts and Sciences, created a sensor reactive to even minute amounts of nitric oxide, a gas prevalent in the breath of asthmatics, as described in the August 22, 2007, online edition of the journal Nanotechnology. The sensor consists of a carbon nanotube-a rolled, 1-atom thick sheet of graphite 100,000 times smaller than a human hair-coated with a polyethylene imine polymer.
Star cased the sensor in a hand-held device that people blow into to determine the nitric oxide content of their breath. The nitric oxide level in the breath of a person with asthma spikes as the airways grow more inflamed. High levels-perhaps two-thirds over normal-may precede an attack by 1 to 3 weeks, but possibly earlier depending on the asthma's severity, said Jigme Sethi, MD, a Pitt assistant professor in the School of Medicine's Division of Pulmonary, Allergy, and Critical Care Medicine and a clinician at UPMC Montefiore, who plans to clinically test Star's sensor.
Besides detecting attacks early on, Star's device would also provide an easy, portable method for patients and their doctors to regularly monitor their symptoms and tailor treatment accordingly, Sethi said. Physicians use nitric oxide readings to help diagnose and gauge the severity of asthma, but the current method of measuring it requires expensive machines available only in outpatient clinics, Sethi said. Star's invention could allow people with asthma to watch their nitric oxide levels as easily as people with diabetes check their blood sugar with hand-held glucose monitors, Sethi said.
Star specializes in using carbon nanotubes-which were widely introduced to science in the early 1990s-as chemical sensors and in hydrogen fuel cells. In the case of sensors, a nanotube's extreme thinness renders it extremely sensitive to small changes in their chemical environment, which makes for an excellent detector, Star said.
So far, Star's device has not been tested on patients-his studies were done in laboratories using gases that simulate a person's breath-but Sethi is planning clinical trials. Star and Sethi would then need to find a drug or medical device company to market it and seek U.S. Food and Drug Administration approval. Likely, it will be several years before the device is commercially available.
Illustration: MicroSoft clipart.
PC Mag (08/17/07)
Extreme Tech (08/17/07)
University of Pittsburgh News (08/22/07)
Nanotechnology Now (08/22/07)
Pittsburgh Tribune-Review (08/22/07)
Nanotechnology Abstract (2007 Nanotechnology 18 375502 (7pp))