'Optical dog's nose' to sniff out diseases

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Scientists from the University of Adelaide, Australia have developed a laser system for fast, non-invasive, onsite breath analysis, potentially enabling screening for a range of conditions including diabetes, infections and various cancers in the future.

Published in the journal Optics Express, the researchers refer to the system as an ‘optical dog's nose’, which uses a laser to ‘sniff out’ and measure the molecular content of a sample of gas.

‘Rather than sniffing out a variety of smells as a dog would, the laser system uses light to ‘sense’ the range of molecules that are present in the sample,’ explained Dr James Anstie, Australian Research Council (ARC) Research Fellow with the University's Institute for Photonics and Advanced Sensing (IPAS).

‘Those molecules are by-products of metabolic processes in the body and their levels change when things go wrong. There have been good studies undertaken around the world which show that diseases like lung and oesophageal cancer, asthma and diabetes can be detected in this way, even before external symptoms are showing,’ Anstie added.

‘One of the nice things about it is that we can detect molecules that dogs can’t, and with very precise quantification of what’s there.’

Breath analysis is a relatively new field being pursued around the world. But the system being developed offers almost-instant results, high sensitivity and the ability to test for a range of molecules at once  ̶  making it promising for broadscale health screening.

In the Optics Express paper, Dr Anstie and colleagues detail their use of optical spectroscopy to detect the light-absorption patterns of different molecules. The system uses an optical frequency comb that sends up to a million different light frequencies through the sample in parallel. Each molecule absorbs light at different optical frequencies and therefore has a unique molecular fingerprint.

‘We now have a robust system to be able to detect the presence and concentrations of molecules in a sample,’ Anstie commented. ‘The next step is to work out how to accurately sample and interpret the levels which will naturally vary from person to person.’

A working prototype is expected to be finished in 2-3 years and a commercial ‘plug and play’ product could be available in 3-5 years. Other potential applications include measuring trace gasses, such as atmospheric carbon dioxide, and detecting impurities in natural gas streams.

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Further information

University of Adelaide’s Institute for Photonics and Advanced Sensing

YouTube clip of optical set up