We all know a breathalyzer as a tube that a policeman asks you to breath into to check if you have been drinking before driving. But our breath can reveal much more: turns out that diseases have their own breathprints, and very soon we may be able to use portable devices to diagnose them.
Recreating a dog’s noseIf you have a dog, you may have noticed that it “feels” when you are sad, or angry, or happy; and many stories tell of dogs warning their owners of an impending heart attack or diabetic crisis. There is nothing magical about it: with their unbelievably sensitive noses, dogs smell tiny particles in our breath, called VOCs (volatile organic compounds), which are released together with many hormones. Scientists now realize that the composition of VOCs in our breath depends greatly on our health, and that various diseases have their own associated VOCs, though the concentrations are tiny – about 1 part per million! To identify these particles, you need exceptionally sensitive equipment (more on the VOC science here). Many teams are currently working on diagnostic devices, most with two-layer filters: a carbon layer to catch VOCs and a layer of atoms that change their resistivity depending on which VOCs come in contact with them.
Cancer and diabetesIt’s long been known that Type 1 diabetes is associated with high levels of isoprene and acetone in the breath; and since diabetes often remains undiagnosed for a long time, a breathalyzer that “catches” it early would be extremely useful. Two projects – in Oxford and in Cambridge – have already created such devices, and soon there may be no need for diabetic patients to prick their finger every day. Cancer is another disease that breath scientists are aiming at: for example, 23 different breath markers have been identified for lung cancer (see the study here). Many forms of cancer have few symptoms and are often diagnosed too late, and a breathalyzer – which could identify, say, lung cancer with over 90% accuracy – will certainly save many lives.
One device for 17 diseases?How close are we to such medical breathalyzers? They already exist. A research team from Israel has built a device able to detect 17 different diseases for which VOC markers are known, including ovarian and breast cancer, liver failure, and IBS (see here for original research). The breathalyzer needs further testing but will probably be available to doctors in the next couple of years. And what about devices that anyone can use and put into their pocket? A team in Australia is working on a breathalyzer that you will be able to slot into your smartphone to check yourself for the same 17 illnesses. Such a tiny device has to be incredibly sensitive; right now it can sense up to 8 diseases and will probably enter the market in three years or so.
Breathalyzers for fitness fansIt’s not just about diseases, however. According to a recent paper, special VOCs are released when a exercising person starts burning fat (lipolysis) as opposed to burning sugar for energy (glycolysis). The new sensor developed in Zurich will allow all those who work out to know exactly when they enter that coveted fat-burning zone without any expensive blood tests – just by blowing into a tube.
Even ancient Greeks knew that the smell of bodily emissions can say a lot about the person’s health, and kings’ physicians would smell royal urine on a daily basis. We live in a time of more invasive and expensive diagnostic methods – blood tests, X-rays, MRIs, etc. However, we may be on a verge of a new medical era, when cheap and precise breath diagnosis will be available to all.