Exhaled breath contains chemical markers that reveal important insights about the body’s internal state, including the presence of diseases such as lung cancer. Developing ways to detect these compounds could enable earlier diagnoses and improve patient outcomes. In a recent study published in ACS Sensors, researchers introduced highly sensitive, nanoscale sensors that, in small-scale tests, identified a significant chemical change in the breath of individuals with lung cancer. This work comes during Lung Cancer Awareness Month in November.
Exhaled breath is composed of various gases, including water vapor, carbon dioxide, and a range of volatile organic compounds. One compound of interest, isoprene, shows decreased levels in the breath of those with lung cancer. Detecting such subtle changes requires sensors capable of measuring isoprene in the parts-per-billion (ppb) range while distinguishing it from other similar chemicals and remaining effective in the presence of natural breath humidity. Previous sensor designs have often involved metal oxides, such as indium oxide, a promising material. The research team led by Pingwei Liu and Qingyue Wang aimed to optimize indium oxide-based sensors for detecting isoprene at naturally occurring levels.
The team created a series of indium(III) oxide (In2O3)-based nanoflake sensors and discovered that one variant, called Pt@InNiOx for its composition of platinum (Pt), indium (In), and nickel (Ni), achieved the best performance. The Pt@InNiOx sensors:
- Detected isoprene concentrations as low as 2 ppb, significantly improving on previous sensors.
- Showed high selectivity for isoprene over other volatile breath compounds.
- Maintained consistent performance across nine simulated use cycles.
As reported by news-medical.net, notably, real-time analysis of the sensors’ structure and electrochemical behavior indicated that the uniform distribution of Pt nanoclusters on the nanoflakes catalyzed the activation of isoprene sensing, enhancing the sensor’s sensitivity.
To demonstrate potential medical applications, the researchers integrated the Pt@InNiOx nanoflakes into a portable sensing device. They tested this device using breath samples collected from 13 individuals, including five with lung cancer. The device successfully detected isoprene levels below 40 ppb in samples from participants with lung cancer, compared to over 60 ppb from cancer-free participants. According to the researchers, this technology could revolutionize non-invasive lung cancer screening, potentially improving early detection, treatment outcomes, and saving lives.