Digitising human smell could help doctors with diagnosis

SMELLODI project

Czech scientists are collaborating on an international project, SMELLODI, which aims to digitise human scent. At the moment it is not yet possible to record a smell, send it halfway around the world and then regenerate it, but SMELLODI is trying to make that possible. And it could have real and beneficial applications in medicine.

The power of smell for diagnosing disease has only started to be recognised in recent years.

The incredible case of Joy Milne, a Scottish woman with a heightened sense of smell who, using only her nose, is able to detect Parkinson’s disease in people many years before they develop symptoms, helped scientists at the University of Manchester to develop a simple diagnostic test for the disease – something which hadn’t existed up until then. Smell has also been used to diagnose cancer and even Covid, with dogs trained to sniff out the diseases in people early, before other kinds of diagnostic tests are able to pick anything up.

SMELLODI project | Photo: Zuzana Machálková,  Czech Radio

But our scent could reveal even more information about us. A team of Czech scientists are working on digitising human scent and trying to figure out what each aspect of our smell indicates, as Robert Hanus of the Czech Academy of Sciences’ Institute of Organic and Biochemistry elaborates.

“What in our complex human scent, which contains hundreds to thousands of individual compounds, might be an indicator of disease, what might be a hallmark of biological sex, of age, and so on. One day it might be possible to simplify this information, miniaturise it, and put it onto tiny chips that will communicate it in an intelligible way to doctors.”

The hope is that one day it might be used in medicine as a diagnostic and monitoring tool, with human odours being analysed as simply and routinely as we use digital thermometers today. Digitising smell could, in the future, also allow odours to be transmitted remotely, just like images and sounds are nowadays.

To digitise human scents and smells, first a sample is taken, for example from someone's armpit using a cotton swab, and then the scientists use a state-of-the-art device – a two-dimensional gas chromatograph, which has the ability to separate individual odour components, and also includes an olfactory port, allowing researchers to send them directly into a person's nose and monitor their subjective reactions to the scents. This high-end technology then allows them to see the digitised human scent in the form of a graph.

“Here, for example, we can look at the odour profile of a person when they feel calm and a person who has just had an unpleasant stressful conversation. A stressed person has much more fluctuations on the chart.”

SMELLODI project | Photo: Zuzana Machálková,  Czech Radio

Before this, Hanus and his colleagues had used the machine to investigate how insects communicate with each other through smell.

“Sooner or later we realised that these wonderful devices and procedures could be used to investigate different questions that are more important for humanity. And so we played with the device casually at first, and tried to distinguish the body odours of members of our laboratory from one another. And we were surprised to find that it worked.”

The discovery that his research was also applicable to humans allowed Hanus and his group to apply to join the already up-and-running international SMELLODI project, which brings together seven scientific and technological institutions from Germany, Israel and Finland with the aim of creating the prerequisites for digitising human body odour to expand diagnostic or health monitoring capabilities in the future. He was successful, beating more than 80 other applicants, and he and his team are now contributing to the project by sharing their knowledge in the field of chemical analysis of volatile substances.

Authors: Anna Fodor , Zuzana Machálková
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