Detect lung cancer in breath

Exhaled breath contains chemical clues of what is happening inside the body, including diseases such as lung cancer. Finding ways to detect these compounds could help doctors make early diagnoses and improve patients’ treatment prospects.

Scientists have developed ultrasensitive nanoscale sensors that, in small-scale tests, detect a key change in the chemistry of the breath of people with lung cancer.

Humans exhale many gases, such as water vapor and carbon dioxide, as well as other airborne compounds. A team led by Ye Cheng of Zhejiang University in the Chinese city of Hangzhou has determined that a decrease in an exhaled chemical, isoprene, may indicate the presence of lung cancer. However, to detect these small changes, a sensor would have to be highly sensitive, capable of detecting isoprene levels in the parts per billion (ppb) range. It would also have to differentiate isoprene from other volatile chemicals and tolerate the natural moisture of breath. Previous attempts to design gas sensors with features like these have focused on metal oxides, including one especially promising compound made from indium oxide.

Ye Cheng’s team set out to refine indium oxide-based sensors to detect isoprene at the level found naturally in breath.

The researchers developed a series of nanosheet sensors based on indium(III) oxide (In2O3). In experiments, they found that one type, which they called Pt@InNiOx because of the platinum (Pt), indium (In) and nickel (Ni) it contains, worked best.

Sensors of this type detected isoprene concentrations as low as 2 ppb, a sensitivity that far exceeded that of previous sensors. Additionally, they responded to isoprene more than other volatile compounds commonly found in breath. Furthermore, they performed consistently over nine simulated uses.

More importantly, real-time analysis of the structure and electrochemical properties of the nanosheets revealed that platinum nanoclusters anchored uniformly on the nanosheets catalyzed the activation of isoprene sensing, resulting in ultrasensitive operation. .

These nanosheets show promise for detecting lung cancer by observing changes in breath chemistry. (Image: adapted from ACS Sensors 2024, DOI: 10.1021/acssensors.4c01298)

Finally, to show the potential medical use of these sensors, the researchers incorporated the Pt@InNiOx nanosheets into a wearable sensor device. Into this device they introduced the breath previously collected from 13 people, 5 of whom suffered from lung cancer. The device detected isoprene levels below 40 ppb in samples from participants with cancer and above 60 ppb in samples from participants without cancer. According to researchers, this screening technology could be a breakthrough in non-invasive lung cancer detection and has the potential to improve outcomes and even save lives.

Ye Cheng and his colleagues present the technical details of their new class of sensor and how it works in the academic journal ACS Sensors, titled “Ultrasensitive In2O3-Based Nanoflakes for Lung Cancer Diagnosis and the Sensing Mechanism Investigated by Operando Spectroscopy.” (Source: American Chemical Society)