A breathalyzer that detects diseases? We are truly living in the future.
In fifth century BCE, Hippocrates wrote a treatise on breath aroma and disease, advising physicians to smell their patients’ breath to detect any number of maladies. The practice has a long history, but it wasn’t until the 1970s when modern medicine took the notion seriously, as famed scientist Linus Pauling identified 250 different substances in exhaled breath, setting the stage for breath-based diagnoses.
Since then, researchers have used gas chromatography and mass spectrometry to identify over 3,000 compounds that are regularly exuded from the body, including through exhalation. No surprise, then, that dogs have been recruited to pick out different forms of cancer, including one dog named Lucy in the U.K., profiled earlier this year on CNN for her ability to sniff out bladder, kidney and prostate cancers at an accuracy rate of 95 per cent. Or African giant pouched rats who have been put to service in Mozambique to smell out cases of tuberculosis.
Now, researchers at the Technion-Israel Institute of Technology in Haifa, Israel, have used nanotechnology to develop a range of tiny sensors that can detect specific molecular compounds in breath samples, creating a disease-recognizing breathalyzer.
Researchers collected 2,808 breath samples from 1,404 subjects who had one of 17 different disease types, divisible into three categories – cancerous, inflammatory and neurological. Through blind experiments, they found that the nanosensors were able to identify the right diagnosis 86 per cent of the time.
As well, researchers determined that each disease carries its own chemical blueprint, based on a specific combination of 13 different volatile organic compounds.
“We found that just as we each have a unique fingerprint, each of the diseases we studied has an unique breath print, a ‘signature’ of chemical components,” says Hossam Haick of the Department of Chemical Engineering and Russell Berrie Nanotechnology Institute at the Technion-Israel Institute of Technology and study co-author. “We have a device which can discriminate between them, which is elegant and affordable.”
The team estimates that their results can be used to create inexpensive, noninvasive and portable biomedical devices, projected to cost as little as $40. “Overall, these findings could contribute to one of the most important criteria for successful health intervention in the modern era,” says the study’s authors.
The new research is published in the journal ACSNano.
Earlier this year, the relevance of the sense of smell was revealed in another way, as researchers at the Alzheimer’s Association International Conference in Toronto, Ontario, presented their findings on odour identification as an early predictor of the transition to dementia. Researchers gave scratch-and-sniff strips to 397 patients and found that those who had been diagnosed with dementia performed worse than others on an odour identification test. The results show the potential use of a simple odour test to help in the early identification of Alzheimer’s. Presenting author, Seonjoo Lee, PhD, assistant professor of clinical biostatistics in psychiatry at Columbia University said that the findings, “support odour identification as an early predictor and suggest that impairment in odour identification may precede thinning in the entorhinal cortex in the early clinical stage of Alzheimer’s disease.”
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