"Electronic Nose" To Detect Exposure to Hazardous Toxins

Photo: Kenneth S. Suslick, Ph.D., the M.T. Schmidt Professor of Chemistry at the University of Illinois at Urbana-Champaign. (Courtesy U. of Illinois)

Dr. Garry Gordon, one of the co-founders of the American College for Advancement in Medicine (ACAM), maintains that the air we breathe, the food we eat, and the water we drink is contaminated with toxins. And these, he says, are slowly destroying human health and well-being.

"The Earth has become so totally polluted that everybody today is walking around with high levels of styrene, PCBs, and dioxins. They're in every human being we test today, as well as is lead, mercury, and cadmium... There is simply no escape from the particulate matter. We have poisoned our nest," Dr. Gordon said in a recent book - Protecting Yourself from Lead, Mercury, & Other Environmental Toxins.

The role that environmental toxins pay in promoting many diseases is still a cloudy medical subject. And determining what minimum levels of exposure bring associated risks is even more uncertain.

However, there is a new tool on the horizon which will enhance worker safety in the workplace, especially for emergency responders and others who often have to deal with unknown toxic environments. It is a polka-dotted postage stamp-sized sensor that can sniff out known poisonous gases and toxins and show the results simply by changing colors.

While physicists have radiation badges to protect them in the workplace, up to now, chemists and workers who handle chemicals do not have equivalent devices to monitor their exposure to potentially toxic chemicals.

But beyond a simple safety measure, the new device could provide a wealth of new information for assessing health risks accompanying any exposure to toxic chemicals.

"The project fits into the overall goal of a component of the GEI Exposure Biology Program that the National Institute of Environmental Health Sciences (NIEHS) has the lead on, which is to develop technologies to monitor and better understand how environmental exposures affect disease risk," said NIEHS Director Linda Birnbaum, Ph.D, in a prepared statement. "This... brings us one step closer to having a small wearable sensor that can detect multiple airborne toxins."

What is this new technology? Kenneth S. Suslick, Ph.D., the M.T. Schmidt Professor of Chemistry at the University of Illinois at Urbana-Champaign and his colleagues have created what they refer to as an optoelectronic nose - an artificial nose for the detection of toxic industrial chemicals (TICs) that is simple, fast, inexpensive, and works by visualizing colors.

"We have a disposable 36-dye sensor array that changes colors when exposed to different chemicals," explained Suslick. The pattern of the color change is a unique molecular fingerprint for any toxic gas and also tells us its concentration. By comparing that pattern to a library of color fingerprints, we can identify and quantify the TICs in a matter of seconds."

The researchers say older methods relied on sensors whose response originates from weak and highly non-specific chemical interactions, whereas this new technology is more responsive to a diverse set of chemicals. The power of this sensor to identify so many volatile toxins stems from the increased range of interactions that are used to discriminate the response of the array.

To test the application of their color sensor array, the researchers chose 19 representative examples of toxic industrial chemicals. Chemicals such as ammonia, chlorine, nitric acid and sulfur dioxide at concentrations known to be immediately dangerous to life or health were included. The arrays were exposed to the chemicals for two minutes. Most of the chemicals were identified from the array color change in a number of seconds and almost 90 percent of them were detected within two minutes.

The laboratory studies used inexpensive flatbed scanners for imaging. However, the researchers have also developed a fully functional prototype handheld device that uses inexpensive white LED illumination and an ordinary camera. This would make the whole process of scanning more sensitive, smaller, faster, and even less expensive. It will be similar to a card scanning device.

"One of the nice things about this technology is that it uses components that are readily available and relatively inexpensive," said David Balshaw, Ph.D., a program administrator at the NIEHS. "Given the broad range of chemicals that can be detected and the high sensitivity of the array to those compounds, it appears that this device will be particularly useful in occupational settings."

The researchers hope to be able to market a fully developed, wearable sensors within a few years.

This report in part was compiled from news releases.