PHOTONICS researchers at the University of Adelaide are developing an instrument that works like an 'optical dog's nose', quickly and accurately detecting molecules in gas samples for medical and industrial applications.
"Every so often in the media, you see these stories that dogs can detect whether there's something going wrong with your body by how your breath smells," says Dr James Anstie.
Whereas dogs go by smell, the spectrometer that Dr Anstie and his team have developed measures the molecular content of gas - potentially clueing doctors in to diseases before symptoms start to show.
"We think dogs are great, but they're not as easy to tame as light."
There have been good studies which show that diseases like lung and oesophageal cancer, asthma and diabetes can be detected in this way.
Dr James Anstie is an ARC Research Fellow and theme leader at the University of Adelaide's Institute for Photonics and Advanced Sensing.
"The fundamental process is spectroscopy, which has been around for many years. What makes us different is our light source. We use something called an optical frequency comb," Dr Anstie says.
An optical frequency comb is essentially a broadband light source made up of millions of distinct, equally spaced laser sources. This appears as a rainbow of light to the naked eye, but the discrete laser sources can be made out under magnification.
"This means you can do a lot of tricks that you can't with normal white light. One of those tricks allows you to increase the sensitivity, really amp it up. Another trick allows you to really accurately and really precisely understand the optical frequency," Dr Anstie explains.
"With those two advantages, you can pull out really high sensitivity and high detail spectra, which is great, and you can do that really, really fast. It takes maybe a few hundred millisecond to pull out a measurement."
The potential for this instrument lies in pairing it with cutting edge medical research on 'breath analysis'; detecting molecules that are by-products of metabolic processes in the body 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."
Dr Anstie says his work is 'the easy part' - measuring molecules in a gas sample. The next step will be bringing in medical professionals who can properly analyse such data.
"That is not a trivial problem, but it's something that people are working on actively at the moment. The nice thing is that it's completely non-invasive. You can get someone to breathe in to a box. It's not scary, it's quick, and you can get people through in a few minutes when it would take a lab worth of gear to figure out what's going on normally."
There's also potential for industrial and environmental applications, such as detecting impurities in natural gas streams or measuring atmospheric carbon dioxide levels.
An example of what the device 'sees'. This output represents Hydrogen Cyanide - unlikely (and nasty) to be found in your breath, but good for testing the device. The numbers on the side of the scale represent the amount of light remaining in the beam after transmission through the sample.
The project is about two and a half years in to development, with Dr Anstie's team essentially starting from scratch, now having a 'world standard' instrument.
"The next step is to push that even further," Dr Anstie says.
"I don't see any major impediments to shrinking it down to at least suitcase size. Beyond that, there's even talk of getting them down to mobile size. Admittedly, they would have far more limited performance, but it would still be quite useful."
The spectrometer is still in prototype stage. Within two or three years the team hopes to have an intuitive device which can be presented with a gas sample before returning an accurate report on its molecular composition.
At that point, it will be put in the hands of medical and industrial researchers.
Published in the journal Optics Express, Dr Anstie and colleagues including Masters student Nicolas Bourbeau Herbert, PhD student Sarah Scholten, senior research associate Dr Richard White and IPAS director Professor Andre Luiten detail their use of optical spectroscopy to detect the light-absorption patterns of different molecules, with high levels of accuracy and speed.
The research is funded through the ARC, the Premier’s Research and Industry Fund and a South Australian Government Catalyst Research Grant.