Scientists at JILA have increased the sensitivity of their ten-year-old frequency comb breathalyzer by a thousandfold and can detect additional disease biomarkers – four now, with a potential of six more. Once validated and designed into a portable design, the comb system could offer real-time, non-invasive analysis of human respiration to detect and monitor disease. JILA is jointly managed by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.
The JILA system “takes fingerprints” of chemicals by measuring the colors and amounts of light absorbed when a laser frequency comb is passed back and forth through breath samples loaded into a reflective glass tube. Recent upgrades include a shift in the analyzed light spectrum from the near infrared band to the mid infrared band, where more molecules absorb light, and advancements in optical coatings and several other technologies to achieve detection sensitivity up to ‘at the parts per trillion level.
As described in Proceedings of the National Academy of Sciences, NIST / JILA Fellows Jun Ye and David Nesbitt detected and monitored four biomarkers: methanol (CH3OH), methane (CH4), water (H2O) and a heavy water form (HDO) – in the breath of a volunteer. These are indicators of health conditions such as, in the case of methane, intestinal problems.
Researchers say it is possible to use the same device to detect six other chemicals: formaldehyde, ethane, carbonyl sulfide, ethylene, carbon disulfide and ammonia. In addition, the extension of comb lasers farther in the infrared is expected to significantly expand detection capability and allow the identification of several hundred traces of respiratory chemicals.
JILA researchers demonstrated a prototype of a comb breathalyzer in 2008, but did not develop it further at the time. They have now refocused on it, driven by the possibility of possibly testing for COVID-19.
âWe are really very optimistic and determined to push this technology into real medical applications,â said Ye.
The most widely used analytical technique in breath research is gas chromatography combined with mass spectrometry, which can detect hundreds of molecules exhaled but operates slowly, requiring tens of minutes. Most optical breathalyzers approved by the United States Food and Drug Administration detect only one chemical. JILA is the only institution to have published research on comb breathalyzers, Ye said.
Breath analysis is the primary medical application of frequency combs. The combs offer a combination of wide spectral coverage, high resolution and high sensitivity, potentially detecting dozens of chemicals simultaneously. Among other advantages, the comb system would not require chemical reagents and complex laboratory facilities.
Ye and Nesbitt are now working with other NIST researchers to design a compact version of the breathalyzer. The tube is only 55 centimeters (21.7 inches) long, but the laser comb is custom made and a bit bulky.
“Comb” laser systems measure all primary greenhouse gases in the air
Qizhong Liang et al, Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnosis, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073 / pnas.2105063118
Quote: Comb breathalyzer is now a thousand times more sensitive to disease biomarkers (2021, October 4) retrieved October 4, 2021 from https://phys.org/news/2021-10-breathalyzer-thousandfold-sensitive -disease-biomarkers.html
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