Researchers at Northwestern University in Evanston, Illinois, are developing a substance that could one day protect people from deadly chemicals.
The research began over a decade ago with one big goal: finding ways to protect soldiers from chemical weapons, particularly nerve agents. These are especially dangerous because of how quickly they can act. They disrupt the nervous system, essentially disconnecting the brain from the rest of the body. Severe exposure can cause seizures, paralysis, and death within minutes.
Military personnel are not the only ones who could benefit from better protection. Many civilian occupations also involve exposure to hazardous chemicals: farmers handle potentially toxic pesticides, while workers in chemical manufacturing deal with dangerous substances every day.
Existing protective clothing simply acts as a physical barrier between the skin and hazardous chemicals.
The researchers are now developing a compound that goes further, by breaking down and deactivating nerve agents. What they are working on is not a new type of fabric, but a chemical that can be applied to any fabric. Think of it as a special coating that adheres to the fabric pretty much like a dye, but instead of changing its color, it changes its chemical properties.
In 2015, the Northwestern research team discovered that zirconium-containing materials could help break down toxic chemical agents. What’s different this time is the combination of zirconium and allomelanin, a melanin-like pigment found in fungi. It not only provides pigmentation but also absorbs small molecules and heavy metal ions. Its porous structure traps tiny harmful molecules, like a microscopic sponge, while zirconium destroys them. On top of that, water serves as a catalyst and activates the chemical reaction.
And this is where things get more complicated. Breaking down a toxic chemical doesn’t mean it disappears without a trace. Chemical reactions produce byproducts, and some of these can be just as dangerous as the original substance. And that was exactly the case. The allomelanin-zirconium reaction produced two byproducts: nontoxic dimethyl phosphate and extremely toxic methyl nitrophenyl.
This is where allomelanin comes into play again. Besides helping capture the original chemical agent, it also binds to the methyl nitrophenyl and reduces its concentration to a level at which it is no longer harmful.
In laboratory experiments, the concentration of the toxic methyl nitrophenyl decreased by 50% within 10 minutes, which is a very promising result. Adding more melanin and exposing the material to sunlight helped reduce its toxicity even further, although the researchers didn’t specify exactly by how much.
"We have worked on melanin for over 12 years, trying to learn about its myriad functions in nature and learning how to optimize, develop and engineer mimetic materials for scalable, translational applications," says Prof. Nathan Gianneschi, co-author of the study. "This provides us with a treasure trove of approaches and materials to optimize and develop for applications like this. In many ways, it’s a proof of concept for a new direction in how we think about protective materials and coatings design."
There is still a long way to go between successful laboratory tests and the mass production of a material that can reliably protect people on the front lines. More research is needed to determine how well this technology performs under real-world conditions, but this research is a huge step toward developing a formula that could one day save countless lives.
A paper on the research was recently published in the journal ACS Nano.
Source: Northwestern University