Portable breath analysis: Johns Hopkins, U of Missouri report mid IR, opto-fluidic ring resonator approaches

MARCH 12, 2009--Today at Pittcon, Terence H. Risby of Johns Hopkins University (Baltimore, MD) demonstrated that clinical breath analysis offers unique and appealing capabilities for disease diagnosis and monitoring. He said mid-infrared (IR) technologies will likely enable the greatest level of portability. As if on cue, the University of Missouri (Columbia, MO) reports that Prof. Xudong Fan is developing an optical sensor to analyze breath for cancer, diabetes or asthma.

MARCH 12, 2009--Today at Pittcon, Terence H. Risby of Johns Hopkins University(Baltimore, MD) demonstrated that although clinical breath analysis is in its infancy, the approach offers unique and appealing capabilities--not the least of which is noninvasiveness (especially compared to blood and tissue collection)--for disease diagnosis and monitoring. Just a few breath monitors are currently available--and most are "transportable but not portable"--but real-time hand-held detectors are being actively developed, and mid-infrared technologies are likely to enable the greatest level of portability, Risby noted. His presentation, called "Real time breath analysis for clinical studies," was part of a session titled "Biomedical Spectroscopy--The New Frontier for Applications of Miniature Spectrometers."

As if to illustrate Risby's point, the University of Missouri(Columbia, MO) reports this week that Xudong "Sherman" Fan, an investigator in its Christopher S. Bond Life Sciences Center, is developing a device to analyze breath samples--or urine--for volatile markers inside the body that indicate disease. These markers, such as alkanes, acetones or nitric oxide, can be used for diagnosis of breast cancer, lung cancer, diabetes or asthma.

"Little traces of certain gas molecules in the breath or urine tell us if anything unusual is going on in the body," said Fan. "Measuring these volatile markers would be a non-invasive way to determine if a disease is present without having to draw blood or complete a biopsy. In addition to the biomarkers already discovered, many more potential volatile markers are still under investigation."

The sensor device known as the opto-fluidic ring resonator (OFRR) is an optical gas sensor that consists of a polymer-lined glass tube that guides the flow of a gas vapor and a ring resonator that detects the molecules that pass through the glass tube. As the gas vapor enters the device, molecules in the vapor separate and react to the polymer lining. Light makes thousands of loops around the gas or liquid sample. The more the light loops around the sample, the more the light energy interacts with the gas vapor. These repetitive interactions enable the detection of vapor molecules down to a very small quantity.

Optical gas sensors have broad applications in the fields of industry, military, environment, medical care and homeland security. Existing gas vapor sensor technology is very bulky with equipment weighing more than 100 pounds and is difficult to use in the field.

"We hope to design a vapor sensor that has ultra-high sensitivity, specific and rapid response to a certain molecule, as well as the ability of on-the-spot chemical analyses, which usually requires the sensor to be small, portable, reusable and have less power consumption," said Fan, who also is assistant professor of biological engineering in the MU College of Engineering and the MU College of Agriculture, Food and Natural Resources. "If the gas sensor is portable, military personnel can determine more quickly whether an area is dangerous."

More information:
See information about Terence H. Risby's work on the Johns Hopkins site.
See also further details about Xudong "Sherman" Fan's work at the U of Missouri's Christopher S. Bond Life Sciences Center.

Reported by Barbara G. Goode, barbarag@pennwell.com, for BioOptics World.

More in Spectroscopy