Dogs and bees can smell disease, so can nanosensors

Dr Noushin Nasiri at Macquarie University

Dr Noushin Nasiri at Macquarie University

Dogs use their superb sensing capabilities to detect a range of smells from explosives to low blood sugar levels in people living with diabetes. When sniffing people, dogs can detect hormonal fluctuations, diseases such as different types of cancer and even depression. Dr Noushin Nasiri, inspired by the canine's smelling capabilities, has developed a nanosensor that can detect changes in human biochemistry much faster than the routine medical examinations.  

"I'm working on small sensors that can analyse human breath and pick some elements in the breath that could be related to the development of a disease in the body," said Dr Nasiri. "Disease development changes the chemistry of our body, and the changes can happen everywhere; in the composition of urine, blood, sweat, saliva and also breath."

Dr Noushin Nasiri (PhD in Nanotechnology) is a lecturer and group leader at the School of Engineering at Macquarie University, a member university of the NSW Smart Sensing Network. Dr Nasiri's research is focused on developing nanostructured materials for health and energy application. With over 50 centres of excellence, collaborative research centres and industrial training centres spread across the NSW Smart Sensing Network, access to world-class equipment is readily available.

"Our breath is a mixture of nitrogen, oxygen, carbon dioxide, water, and only 1% of other gases. That 1% includes thousands of biomarkers which can help me to detect diseases such as diabetes, breast cancer, kidney failure and lung cancer" said Dr Nasiri. 

The biomarkers concentration difference between healthy people and patients is parts per billion. Dr Nasiri's fingertip-sized sensor is made of billions of nanoparticles, that each has a diameter of a few atoms that enable the sensor to be sensitive enough to detect tiny biomarker concentrations in the human breath. These small sensors can help to both detect and monitor medical conditions non invasively. For instance, diabetic patients can use the sensors to monitor blood sugar levels. 

"In nanotechnology, everything is related to the surface area, if you have more surface you have a higher chance to capture that concentration," added Dr Nasiri, "We try to increase the surface which means having more receptors, that [detect] lower concentrations with higher sensitivity."

Sensors usually are bulk, therefore gasses react to the surface area which as a result enables the sensor to show indicative signs, such as a change in colour. Dr Nasiri's work is on metal oxide sensors, but what makes her sensor unique is its design. 

"My sensor is made of only 2 per cent bulk material and 98 per cent air; it's like a super spongy sponge made of air with thin bridges of particle everywhere. So the gas reacts not only with the surface, but it reacts to a whole volume," said Dr Nasiri, "Then you have a chance to pick a very tiny concentration, and that's how you can detect diseases."

Dr Noushin Nasiri from Macquarie University holding her nanosensor

Dr Noushin Nasiri from Macquarie University holding her nanosensor

Dogs and bees are known to be able to detect particles per trillion. "My sensor at the lowest concentration can detect two particles per billion. Which can cover a lot of diseases because diseases are mostly on particles per million and per billion," said Dr Nasiri. "Some diseases go to particles per trillion, we can't detect those but dogs and bees can detect particles per trillion."

Bees are easy to train for scent detection says Dr Nasiri. For instance, if the aim is to detect acetone, a bee is first exposed to the acetone vapour for four seconds and then is given sugar for two seconds. This process is repeated for eight minutes. After this training, every time that the bee can smell acetone, it sticks its tongue out looking for sugar which is recorded by tiny cameras installed on the bee's head. 

"In eight to twelve minutes you can be confident that your bees can actually detect the biomarkers, but they normally die after one and a half months, so every one and a half months you have to train new bees." Dr Nasiri said.

Dr Nasiri is hoping her sensor can help people to detect medical conditions early and more accurately. For instance, she said, in the case of breast cancer detection, the first testing method is a mammogram X-ray, that is done every few years and is only 70% accurate. 

"What I hope is for my breath analysis sensor to be the first test, we can do the breath analysis every day, or every month and if it's [the results] are negative is ninety nine percent accurate and you don't have the disease," said Dr Nasiri, "I'm hoping that my sensor can give us some signals about our health and help us to go to the doctor more frequently."

"We want people to believe that this can change the future of medicine and save people's lives," Dr Nasiri added.  

Dr Noushin Nasiri will be a guest speaker at TEDx Macquarie University which will be held on Saturday 21st September 2019. Noushin will be talking about her research on nanomaterials for health, energy and environmental applications.

Shahrzad Abbasi