Neurotoxins Are A Rising Threat. Here’s How the Military Will Detect Them

If Russian opposition leader Alexey Navalny was, as German leaders say, poisoned with the deadly Soviet-era Novichok neurotoxin, it would once again highlight the willingness of the Kremlin to deploy such toxins in civilian and urban areas — and the urgent need for better ways to detect their use. The U.S. military will soon roll out one such tool: a spray that can alert troops and first responders to the presence of such neurotoxins.

Novichok, a Russian neurotoxin that GRU agents used against double agent Sergei Skripal and his daughter in 2018, is difficult to detect until it’s too late. Same with VX, the neurotoxin that North Korean operatives used against Kim Jong-nam in 2017 — an oily, heavy, non-volatile liquid that doesn’t decompose quickly or vaporize easily. So sensors that detect impurities in the air are largely ineffective.

And that’s most of them, says Stephen Lee, senior scientist at the Army Research Office, including the handheld ion mobility spectrometer sensors deployed with troops around the world. “They rely on being able to detect chemicals primarily in a vapor form. So if that VX is on a surface and it has a very, very low amount and it has no vapor pressure really,” it’s very hard to detect, Lee said.

But brushing up against even a tiny amount of Novichok or VX can kill — either the intended target or some unfortunate passerby. Skirpal survived the neurotoxin, but an unrelated woman who merely happened to be in the wrong place died.

Neurotoxins hijack the acetilcolinesterase enzyme that helps nerves send signals to your muscles. The more efficiently a nerve agent shuts off the flow of that enzyme, the more lethal it is. 

Researchers at FLIR, working under a U.S. Army program, have figured out how to use that biological process to produce a spray that can reveal where difficult-to-trace neurotoxins are sitting on surfaces. In the same way enzymes in your body react when they encounter the neurotoxin, so do the enzymes in the spray, but in the case of the latter, changing color, allowing operators to see clearly where the neurotoxin has landed.

“No other detector has been like this before,” said Lee. “We didn’t have a surface analyzer you could put on the whole surface… There wasn’t this technology before, no capability for us to—pre- or post-decontamination—know exactly where the agent was… With this we know exactly where it is.”

When first responders sought answers after the Skirpal poisoning, they had to gather many environmental samples, then wait for them to be processed at a lab, then painstakingly plot the results on a map. ““That’s a lot more time for the analysts,” said Jeremy Walker, director of science and technology at FLIR, “ a lot more time to not know if you have something on you.” 

But you can’t just recreate enzymes that the body uses for specific functions and expect them to work outside of the body in a similar way. Getting those enzymes into a stable form, capable of working as part of a kit for detection, has been a long and difficult process. The Army has been funding research into stabilizing enzymes for use as detectors for decades now. 

In 2005, FLIR won a small business innovation research contract to show that enzymes in a detection “pen” could change color when it came into contact with different toxins. Last month, they won an award to produce the material at full rate of production for use in a spray, as part of a program called the Contamination Indicator Decontamination Assurance System, or CIDAS.

The spray will tell you where the nerve agent is, but it won’t necessarily tell you the specific kind of toxin you are dealing with. Lee says that the spray in combination with a small device, perhaps the size of a badge, capable of analyzing samples, would provide information about where the toxin is as well as the type, which is the direction CIDAS is moving toward.

“You could develop a badge of microfluidics that would tell you, further define if it's sarin, VX, or some Russian compound. You could get that level of detail using an infomatic processor and it would be much more sensitive to detail than an electronic device because you’re using enzymes,” he said.