The air we exhale carries important chemical indicators of our body’s internal state, including signs of diseases such as lung cancer. Creating methods to detect these compounds could aid physicians in making early diagnoses, ultimately benefiting patient outcomes. In a publication in ACS Sensors, scientists have announced the creation of ultrasensitive, nanoscale sensors that successfully identified a significant alteration in the breathing chemistry of lung cancer patients during initial tests. November is designated as Lung Cancer Awareness Month.
When we breathe out, we release various gases like water vapor and carbon dioxide alongside other airborne substances. Researchers have found that a decrease in isoprene, an exhaled chemical, can signal the presence of lung cancer. Detecting such tiny changes requires an incredibly sensitive sensor, capable of measuring isoprene concentrations in the parts-per-billion (ppb) range. It must also distinguish isoprene from other volatile chemicals and handle the natural humidity in breath. Previous efforts to create gas sensors with these capabilities typically centered on metal oxides, including an especially promising one made of indium oxide. A research team led by Pingwei Liu and Qingyue Wang sought to enhance these indium oxide sensors to accurately detect isoprene levels as they naturally occur in breath.
The team developed a series of indium(III) oxide (In2O3) nanoflake sensors. Their experiments revealed that one specific variant, named Pt@InNiOx because of its platinum (Pt), indium (In), and nickel (Ni) content, exhibited the best performance. The Pt@InNiOx sensors:
- Achieved sensitivity to detect isoprene at levels as low as 2 ppb, significantly surpassing the capabilities of prior sensors.
- Showed a greater response to isoprene than to other volatile compounds typically found in exhaled breath.
- Maintained performance consistency over nine simulated uses.
Additionally, the researchers’ real-time analysis of the structure and electrochemical characteristics of the nanoflakes showed that platinum nanoclusters, evenly anchored on the nanoflakes, facilitated isoprene detection, resulting in highly sensitive performance.
To demonstrate the potential medical application of these sensors, the researchers integrated the Pt@InNiOx nanoflakes into a portable sensing device. They tested breath samples collected earlier from 13 individuals, five of whom were lung cancer patients. The device successfully identified isoprene levels below 40 ppb in samples from those with cancer, while detecting over 60 ppb in samples from those without cancer. This sensing innovation could revolutionize non-invasive lung cancer screening, offering the potential to enhance patient outcomes and even save lives, according to the researchers.
