A portable device, developed in part by EPFL researchers, monitors one's breath to quickly detect the presence of head and neck cancer. The technology, equipped with extremely sensitive sensors, has been tested on patients and operates with a computer or even a mobile phone.
The scientists' starting point was the observation that human breath contains not only air, but also hundreds of volatile organic compounds (VOCs) whose presence and concentration vary depending on the patients' state of health. The metabolism of cancerous cells is different from that of healthy cells, and the two types of cells produce different substances in terms of both quantity and typology. As a result, they leave their "signature" in people's breath.
Each microsensor is composed of a silicon disk 500 micrometers. The sensors are covered by a polymer and suspended by four minuscule "bridges" with integrated piezoresistors. When exposed to a gas, the polymer absorbs certain molecules and the disk changes shape. The deformation is detected by the four piezoresistive bridges, which emit an electrical signal. The phenomenon makes it possible to determine the signature of the gas and its concentration.
