Caution: You Are Being Sniffed by an Electronic Nose!

Researchers are advancing material technologies to develop an “electronic nose”—a groundbreaking device poised to transform medicine, agriculture, industry, and security. This device, capable of analysing air composition, has the potential to detect hazardous substances and biomarkers of diseases, opening new horizons in early diagnosis and environmental monitoring.

Imagine passing through airport security where the “electronic nose” not only ensures safety but also recommends a medical examination. Many diseases, such as cardiopulmonary disorders, cystic fibrosis, or diabetes, are associated with the release of specific organic gases in ultra-low concentrations. For instance, ethanol can indicate cardiopulmonary syndrome or diabetes, while acetone may signal liver cirrhosis or lung cancer.

Recent research conducted by scientists from the Institute of General and Inorganic Chemistry of the Russian Academy of Sciences could revolutionise the creation of such devices. They have developed a nanocomposite material, consisting of zinc oxide and palladium nanoparticles, with remarkable sensitivity to volatile organic compounds such as aromatic hydrocarbons and ketones. This innovation is particularly significant for the development of highly sensitive sensors that can function effectively in humid conditions.

Nanoparticles of zinc oxide (ZnO), measuring 40–50 nm, enhanced with palladium (4–7 nm), enable the creation of sensors that operate with exceptional sensitivity at room temperature. This marks a significant advancement compared to existing technologies, which typically require temperatures ranging from 250–400°C. The use of palladium as a catalyst reduces power consumption and simplifies sensor design.

The nanocomposites demonstrate exceptional sensitivity to acetone concentrations ranging from 100 to 20 parts per billion (ppb) in the air. This level of sensitivity is ideal for ultra-sensitive devices intended for non-invasive disease diagnosis

state the study authors on the website of the journal sciencedirect.com (https://www.sciencedirect.com/science/article/abs/pii/S0925838824034431?via=ihub)

Battle of Technologies: Who Will Create the Best Electronic Nose?

In recent years, research teams worldwide have been actively working to enhance gas sensors. So-called “e-sensors” are being refined not only in terms of technology but also for commercial applications. The global gas sensor market is projected to reach $2.5 billion by 2024, with an annual growth rate of 10% over the next five years. This presents enormous opportunities for mass production of devices based on electronic nose technologies.

One of the most significant contributions to the development of the “electronic nose” has come from scientists studying carbon nanotubes and graphene. Due to its unique structure, graphene enables highly efficient detection of gas molecules. While graphene itself is an excellent material for sensors, researchers are also leveraging transition metal oxides, such as tin, zinc, and titanium oxides, to ensure stable sensor performance under diverse conditions.

Modern “electronic noses” incorporate multiple sensors, each calibrated to detect specific gases. In some cases, these systems include dozens of sensors, significantly increasing accuracy and reliability. Data from these sensors are analysed in real time, making such devices increasingly accessible for applications ranging from disease diagnosis to food quality control and industrial safety.

Examples of Use: From Medical Research to Food Quality Control

“Electronic nose” technologies are already being applied in various industries. In agriculture and the food sector, these devices help monitor the quality of products such as coffee, wine, meat, and fish. For example, studies have demonstrated that sensors can classify the degree of coffee roast and measure acetic acid levels in wine. These applications ensure consistent quality and freshness throughout production and storage processes.

In medicine, “electronic noses” could become invaluable tools for the early diagnosis of diseases such as lung cancer, liver conditions, and diabetes. Since many illnesses release specific gas traces in a patient’s breath, these devices can detect diseases at their earliest stages, when treatment is most effective. Additionally, “electronic noses” could facilitate real-time monitoring of patients’ conditions and predict potential complications.

In safety applications, this technology is used to detect potentially hazardous leaks of methane, hydrogen, or carbon monoxide in industrial and transportation settings. For instance, equipping airplanes and trains with such sensors could enable the timely detection of leaks, protecting passengers’ lives.

Scientific Breakthrough and Prospects

The development of the “electronic nose” owes much to the groundbreaking research of Linda Buck and Richard Axel, who were awarded the Nobel Prize in 2004 for their work on olfaction. They demonstrated that the brain processes signals from multiple receptors simultaneously, allowing humans to distinguish and remember up to 10,000 different smells. This concept forms the basis of electronic noses, which analyse odours using a combination of sensors that respond to various chemical substances.

Today, scientists are focused on improving methods for synthesising and modifying materials used in gas sensors to develop more efficient and affordable solutions. Special attention is being given to nanomaterials, which can be easily tailored for different applications. The emergence of such technologies in the near future could trigger a revolution in healthcare, industry, and household devices.