LOTS OF NERVE: Researchers were able to detect the presence of a nerve agent related to sarin gas at a low concentration of 160 parts per billion using a litmus-like paper sensor designed to change color from blue to pink within 30 seconds of exposure to trace amounts of the toxic gas.
Image: Courtesy of University of Michigan College of Engineering photographer Marcin Szczepanski
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It seems unlikely that the maker of hundred-million-dollar Hollywood blockbusters such as Armageddon and The Transformers could inspire scientists to develop an ultralow-cost tool for quickly sensing airborne chemical weapons. Yet one former University of Michigan at Ann Arbor (U.M.) researcher says his idea to use a nerve-gas antidote to create an inexpensive litmus paper–like nerve-gas sensor emerged shortly after watching The Rock on DVD a few years ago.
During the climax of that 1996 Michael Bay movie, chemical weapons specialist Stanley Goodspeed (played by Nicholas Cage) injects himself in the heart with atropine to prevent certain death from VX gas. After watching the movie with his wife, Jiseok Lee became intrigued by the possibility of using the nerve-agent antidote pralidoxime (also known as 2-PAM) to detect the presence of organophosphate nerve gases such as VX and sarin.
"I was inspired to use an antidote because an antidote always has a nice affinity to poison," says Lee, now a postdoctoral associate in the Massachusetts Institute of Technology's Department of Chemical Engineering. "That was the start of this research."
Lee and his U.M. colleagues were able to detect the presence of a nerve agent related to sarin gas at a low concentration of 160 parts per billion using a litmus-like paper sensor designed to change color from blue to pink (Lee says although it looks pink, technically, it is red) within 30 seconds of exposure to trace amounts of the toxic gas. The sensor combines a group of atoms from a nerve gas antidote with a molecule that changes color when it is under stress, the researchers reported recently in the online version of Advanced Functional Materials.
"The test can be done using a simple filter paper, and the sensory materials can be synthesized quite easily," says Jinsang Kim, an associate professor in U.M.'s Materials Science and Engineering; Chemical Engineering; and Biomedical Engineering departments. Kim, who advised Lee and his colleagues during their research, adds that it costs about $1 for the chemical reagents and solvents used to make each filter.
"This work is very novel in that we don't need complicated lab-scale analytical devices," Lee says. "[With some] technical modification we might be able to easily commercialize the sensor with extremely low cost."
A litmus-paper test is a low-tech alternative to some of the more sophisticated chemical and radiation detection tools developed in recent years. These include self-contained mobile land and airborne laboratories for monitoring air quality, which the U.S. Environmental Protection Agency (EPA) has poured millions of dollars (pdf) into over the past decade. The EPA's Trace Atmospheric Gas Analyzer (TAGA) bus performs real-time sampling and analysis to detect chemicals at very low levels; and the agency's Airborne Spectral Photometric Environmental Collection Technology (ASPECT) aircraft uses chemical and radiological detectors, high-resolution digital photography, video and GPS technology combined with sophisticated software to remotely detect chemicals and radiation. In addition, handheld Chemical Agent Monitor (CAM) devices used by the military and first responders weigh several kilograms and cost upward of $6,500. CAM devices, of course, are also more sophisticated than litmus paper, detecting and discriminating between, for example, vapors of nerve and blister agents and displaying their relative concentration.
Paper-based sensors would be a more practical alternative in equipping large numbers of soldiers and first responders. Litmus paper could warn them to don gas masks, even if specific details about a particular chemical attack aren’t available.
The Michigan researchers are now developing a way for sensory chemicals to self-assemble into nanofibers that could be used to make a new type of sensor device that provides three different sensory signals—color change, fluorescence development and conductivity change—that can alert to the presence of a number of chemical and even biological weapons such as anthrax, Kim says.
Perhaps the biggest litmus test lies ahead—finding a way to commercialization these technologies and put them in the hands of those who need them the most.
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8 Comments
Add CommentHow fast do Sarin or VX gas kill? Is 30 seconds a short enough time to make a difference? TSA could swipe these through luggage and detect potential chemical weapons.
Reply | Report Abuse | Link to thisColor changing paper to detect chemical agents is hardly any new invention. I have 30 years experience in protection against chemical weapons, and this method of detection was around long before I entered this field. One drawback with this type of detection equipment is that you have to do something active to detect an attack. In other words, it will only be of any help if you expect an attack. And then you will put on protective equipment without waiting to see if you can detct an attack. However, simple detectors like this can be used to tell you if it's safe to remove your protective gear.
Reply | Report Abuse | Link to this+1 to what @obusmu wrote. I was trained in NBC (Nuclear, Biological and Chemical) decontamination when I was in the USAF from 73 - 83 and we had something like litmus paper for various chemical agents. I don't remember all the colors possible but I do remember that nerve agents would turn the strips yellow (so would Lysol spray IMS) and blister agents would turn it red IMS. Unfortunately, the concentrations of war gasses needed to incapacitate someone are tiny. If you are getting a color change and you aren't already suited up, about all you can do at that point is stick your head between your knees. We were trained to use the strips to help determine what specific techniques to use in decontamination.
Reply | Report Abuse | Link to thisThe problem in using such technology for early warning is that the detection levels are usually one or more orders of magnitude above toxic levels. I remember in Titan II silos the alarm threshold for fuel (which was 1st cousin to nerve gas) was a good 2 (or was it 3) orders of magnitude above the toxic threshold. The oxidizer alarm threshold was better but then the oxidizer was visible.
If these strips respond like the materials we had when I was on active duty USAF, they are easy to spoof such that a false positive is produced. If enough false positives occur, people will stop believing the alarms, producing a window for a GENUINE attack. For reference read this entry at Wikipedia: http://en.wikipedia.org/wiki/The_Boy_Who_Cried_Wolf
Reply | Report Abuse | Link to thisThe detection paper you used probably responded to liquid agents (chemical rain). An old detection system which can still be obtained, at at price of 387 USD, is the M256
Reply | Report Abuse | Link to thishttp://www.readymaderesources.com/cart//wmd-pandemic-protection-products/chem-detection/m256-kit-free-shipping/prod_676.html
I did some tests on this system many years ago, and found it to be very cumbersome and time consuming, but it detects vapors of nerve agents, blister agents and blood agents. The "new" invention described above apparently only detects nerve agents.
When I was in the USAF, 67 - 71, and stationed on a very remote radome site, we were trained on radiation and chem detection. Didn't help that I am color blind.
Reply | Report Abuse | Link to thisWe found that the best detector was when the man next to you dissolved into a lump of quivering neurons, YOU'RE UNDER ATTACK!
I asked about remediation, the answer? You're officially an XB3 (expendable) asset. I further asked how "they" (the forces back in the lower 48) would know we were expended?
Simple, he answered in all sincerity, we'll stop transmitting back to them. When we go dark, the attack is underway.
Kinda puts the Cold War into a new perspective, eh?
How the Paper-based sensors would help in this..?
Reply | Report Abuse | Link to thisHazMat Experts and Firefighters petition Dow Chemical and Union Pacific for safe rail tank cars transporting gas chlorine. Secondary containment is a necessary improvement that must be implemented. See--PETITION C KIT for First Responders Comments.
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