Researchers may have developed ultrasensitive, nanoscale sensors that distinguished a key change in the chemistry of the breath of patients with lung cancer, according to a recent study published by Cheng et al in ACS Sensors.
Background
Individuals breathe out many gases, such as water vapor and carbon dioxide, as well as other airborne compounds. As a result, exhaled breath can contain chemical indicators of diseases like lung cancer. Devising methods to sense these compounds could help physicians provide early diagnoses and improve patients’ prognoses.
Study Methods and Results
In the study, researchers determined that declines in isoprene may indicate the presence of lung cancer. However, to detect such small shifts, a sensor would need to be highly sensitive—capable of detecting isoprene levels in the parts-per-billion (ppb) range. It would also need to differentiate isoprene from other volatile chemicals and withstand breath’s natural humidity.
Previous attempts to engineer gas sensors with characteristics like these have focused on metal oxides, including one compound made with indium oxide. The researchers set out to refine indium oxide–based sensors to detect isoprene at the level at which it naturally occurs in breath.
The researchers developed a series of indium(III) oxide (In2O3)-based nanoflake sensors. In tests, they found one type—which they named Pt@InNiOx for the platinum (Pt), indium (In) and nickel (Ni) it contains—performed the most effectively. The Pt@InNiOx sensors:
- detected isoprene levels as low as 2 ppb, a sensitivity that surpassed earlier sensors;
- responded to isoprene more than other volatile compounds commonly found in breath; and
- performed consistently during nine simulated uses.
Notably, the researchers’ real-time analysis of the nanoflakes' structure and electrochemical properties revealed that Pt nanoclusters uniformly anchored on the nanoflakes catalyzed the activation of isoprene sensing, leading to the ultrasensitive performance.
Finally, to showcase the potential medical use of these sensors, the researchers incorporated the Pt@InNiOx nanoflakes into a portable sensing device—where they introduced breath collected earlier from 13 patients, 5 of whom had lung cancer. The device detected isoprene levels lower than 40 ppb in samples from participants with cancer and more than 60 ppb from cancer-free participants.
Conclusions
The findings revealed that the sensing technology could provide a breakthrough in noninvasive lung cancer screening and could have the potential to improve outcomes and even save lives.
Disclosure: The research in this study was funded by the National Natural Science Foundation of China, China’s State Key Laboratory of Chemical Engineering, the State Key Laboratory of Electrical Insulation and Power Equipment, the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, the National Key Research and Development Program of China-Young Scientists, the Research Funds of Institute of Zhejiang University-Quzhou, and the Science and Technology Program of the Institute of Zhejiang University-Quzhou. For full disclosures of the study authors, visit pubs.acs.org.
