Gas-sensor device can predict asthma attacks

The portable device works by measuring the level of nitrogen monoxide (NO) on a patient’s breath to determine whether their bronchial tubes have inflamed.

Often the inflammation sets in long before a patient can feel anything. If left untreated, it could lead to severe breathing problems and the patient being hospitalised.

‘Similar sensors to this are currently available in doctors’ offices, but they are too bulky and expensive for individual use,’ said Dr Maximilian Fleischer, who helped develop the device.

Siemens’ sensor, which is slightly smaller than a mobile phone, works by converting NO to nitrogen dioxide (NO₂).

When air flows across the sensor, it selectively catches the NO₂, which gives rise to a small electrical voltage that indicates chemical levels on the breath in parts per billion (ppb).

This high sensitivity provides an early warning and allows patients to adjust their medication accordingly.

‘We use the universal CMOS chip platform, called GasFET by scientists,’ said Fleischer. ‘Different receptor layers can be attached to the platform to adapt it for different applications, such as the detection of fires.’