Researchers at the Univeristy of Rome are developing an electronic nose that can sniff out cancer by sampling people’s breath. The instrument uses sensors that respond to the presence of chemical compounds in the patient’s breath. For example, lung cancer patients exhale alkanes and benzene derivatives which the electronic nose will try to detect. The sensors are quartz crystal sensors coated with a substance that binds to a range of organic chemicals. If certain molecules in the breath bind to this surface coating they change the natural vibration frequency of the crystal.