Sophia Chen of MRS Bulletin interviews Jared DeCoste, a researcher with the US army, about the research team's work to counter the effect of mustard gas. First, the researchers alter E. coli’s DNA to produce an abundance of the molecule protoporphyrin IX. They then mix the protoporphyrin IX with another type of molecule called a metal-organic framework, which then behaves like an absorbent microscopic sponge that detoxifies sulfur mustard, or mustard gas. Read the abstract in MRS Communications (doi: 10.1557/mrc.2019.22).
SOPHIA CHEN: Today we’re talking about new research out of the military on sulfur mustard, or as it’s more commonly known: mustard gas. Researchers are wondering, could you make some sort of clothing protection for a soldier that basically neutralizes the chemical upon contact? Jared DeCoste is a researcher with the US Army developing these smart uniforms.
JARED DECOSTE: We’re doing a lot of research in this area, and we’re excited about the way it’s progressing, and hope to really see these materials being used, at least, in military garments in the coming years.
SC: They’re working to develop a weaveable material containing the mustard-neutralizing molecules. But one of the molecules is extremely difficult to make from scratch. It’s called protoporphyrin IX.
JD: It’s not a very symmetrical molecule. That means we can’t selectively make the functional groups and so forth to make that molecule.
SC: So they needed a different strategy. Fortunately for them, protoporphyrin IX actually occurs a lot in nature.
JD: Protoporphyrin IX is actually a precursor to heme, which is in our cells for absorbing oxygen, and a precursor for chlorophyll, which is used by plants to absorb light.
SC: And it turns out that E. coli cells make protoporphyrin IX in trace amounts. So DeCoste and his team actually went into the E. coli’s DNA and altered it so that the bacteria would produce it in much larger quantities. Then, they mixed the protoporphyrin IX with another type of molecule called a metal-organic framework. These molecules basically act like absorbent microscopic sponges that other molecules like to stick to.
JD: In a typical solid, the only thing to be exposed to be reacted with is the surface. Inherently if you have a sponge or large porous material, everything is a surface. Everything inside your metal-organic framework is readily available to any application you need, be it detoxification, detection, adsorption.
SC: This sponge-protoporphyrin hybrid collectively is really good at detoxifying mustard gas. So far, DeCoste’s team is working with the material in powder form, but they’re also trying to figure out how to make it into fibers that can be weaved. But the work isn’t just about this one application to mustard gas, says DeCoste. It’s a demonstration of how genetically engineered cells can produce molecules that are difficult to make using conventional chemistry processes. This material would not have been possible without the modified E. coli. DeCoste thinks that this whole field, synthetic biology, has a lot of potential to benefit materials science.
JD: The army and the military in general has a bunch of programs looking at ways to exploiting synthetic biology in general for new materials, making new molecules, and things along those lines. There’s a heavy investment in this area, and it’s a really hot topic right now that’s really started to come into its own.
CHEN: This work was published in a recent issue of MRS Communication