Optical ‘frequency comb’ to detect disease through breath

February 20th, 2008 - 2:10 pm ICT by admin  


Washington , Feb 20 (ANI): Painstaking procedures to detect various diseases may soon be a thing of the past thanks to a new breath analyzer that makes use of frequency combs, an optical tool that detects trace amounts of more than 1,000 compounds, of which many may be early disease signals.

A researchers team led by Jun Ye, a physicist at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder, has shown an optical technique for identifying tiny amounts of a broad range of molecules in the breath simultaneously, an would enable a fast, low-cost screening tool for disease.

It is exciting to imagine the potential of analyzing all major biomarkers in ones breath at once. For example, nitric oxide can indicate asthma, but it also appears in breath with many other lung diseases, including chronic obstructive pulmonary disease, cystic fibrosis and bronchiectasis. However, if we simultaneously monitor nitric oxide, carbon monoxide, hydro-peroxide, nitrites, nitrates, pentane, and ethane, all important biomarkers for asthma, we can be much more certain for a definitive diagnosis of this important disease, said Ye.

Other methods, that are currently in use for detecting trace amounts of molecules from the breath are either bulky, slow, limited to specific molecules, unable to distinguish very well between multiple compounds or inaccurate at measuring their concentrations.

Frequency combs are created by a laser specially designed to produce a series of very short, equally spaced pulses of light. Each pulse may be only a few millionth billionths of a second long. This laser generates light as a series of very narrow frequency peaks equally spaced, like the teeth of a comb, across a broad spectrum.

For the experiment, student volunteers exhaled breath that entered an optical cavity where it was combed by the light pulses.

The researchers could detect specific molecules and their concentrations after detecting which colours of light were absorbed and in what amounts, essentially looking for light absorbed near the teeth of the comb. For example, a student smoker who participated in the experiment had a level of carbon monoxide that was five times greater than a nonsmoker in the experiment.

This optical comb approach makes it possible for the researchers to simultaneously analyze a very broad spectrum, covering many possible molecular compounds, with high precision, frequency resolution and sensitivity.

Right now, the technique is in early phases, and clinical trials would be required before it could come in practice, but it could lead to one of the first widespread applications of frequency combs. (ANI)

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