Exhaled breath contains chemical clues to what's going on inside the body, including diseases like lung cancer. And devising ways to sense these compounds could help doctors provide early diagnoses—and improve patients' prospects. In a study in ACS Sensors, researchers report developing ultrasensitive nanoscale sensors that in small-scale tests distinguished a key change in the chemistry of the breath of people with lung cancer. November is Lung Cancer Awareness Month.

People breathe out many gases, such as water vapor and carbon dioxide, as well as other airborne compounds. Researchers have determined that declines in one exhaled chemical—isoprene—can indicate the presence of lung cancer. However, to detect such small shifts, a sensor would need to be highly sensitive, capable of detecting isoprene levels in the parts-per-billion (ppb) range. It would also need to differentiate isoprene from other volatile chemicals and withstand breath’s natural humidity.