In the search for new defenses against chemical, biological and radiological threats, researchers often look toward nature, where simple organisms provide clues for new ideas and new capabilities.

A variety of microbes have the ability to synthesize intracellular metal nanoparticles that could be harnessed for use in future military applications. One of these organisms, the bacteria Magnetospirillum gryphiswaldense, sequesters magnetite to form intracellular chains of microbial nanoparticles called magnetosomes. These biologically-derived nanoparticles require much less energy to make than their synthetic counterparts and have a number of superior qualities such as high chemical purity, low toxicity, good biocompatibility and environmentally-friendly production.

At the U.S. Army Combat Capabilities Development Command (CCDC) Chemical Biological Center biologist Alena Calm, research scientist Kelley Betts, research chemical engineer Michael Kim, Ph.D., and biologist Frank Kragl are developing methods to characterize and scale up the production of these nanoparticles to better understand how biologically-derived nanoparticles could improve Army capabilities.

The initial goal was to explore the ability of these nanoparticles to provide customizable, environmentally-friendly electromagnetic pulse protective materials that fit well within the Army’s Energy Security and Sustainability Strategy. Current capabilities, such as the Faraday cage, can be expensive and cumbersome in field-forward environments.

Now that they have determined how to grow the bacteria on a large scale, they’re investigating military uses for the nanoparticles that they produce. While their use in medicine is well-documented in applications such as magnetic imaging, immunoassays and cancer therapeutics, their potential in military applications remain undiscovered.

“We’ve learned how to grow them in small and large scales. We’ve gotten to the stage of making and characterizing nanoparticles, and we’re in the process of figuring out what they can do,” Calm said. “In the next steps, we’d like to learn about what they can do for the Army. We keep getting more ideas on how to use these.”

Because nanoparticles have both broad and interdisciplinary applications, they could potentially impact the development of a variety of defense-related materials such as new classes of sensors, microelectronic devices, specialized coatings useful for next-generation combat vehicle design and functionalized textiles such as Solider uniforms and protective suit systems.

Currently, scientists at the Center’s Toxicology and Obscuration Sciences Division are electrospinning the nanoparticles in a polymer.

“If we can spin these into fibers, the material could be tested for an assortment of capabilities,” Betts said.

The Center’s Biotechnology Branch is partnering with the University of Delaware’s College of Engineering to determine the possibilities.

This research was jumpstarted through the Center’s FY18 Innovative Development of Employee Advanced Solutions (IDEAS) Program, which is designed to promote innovation and advanced development of new ideas and projects, and was subsequently supported by the Center’s Biological Engineering for Advanced Materials Solutions Grand Challenge. In 2019, the newly-awarded IDEAS project titled: A Biologically-derived Transformer- “More than meets the eye…” will look to leverage these living organic materials to develop a first-of-its-kind, highly efficient, biologically-grown electronic transformer by using living bacterial cultures to grow a working laminated transformer core.

The CCDC Chemical and Biological Center is the first Defense Department laboratory to develop a process for scaling up the production of magnetosomes.

“This organism has been looked at for decades, but we’re the one DoD lab doing so at this scale,” Betts said. “We’re one of the only labs to try this.” Calm explained that the bacteria is notoriously tricky to cultivate. “The hallmark of these organisms is that they’re difficult to grow,” Calm said. “We picked this one because it is considered a ‘lower hanging fruit’ compared to others, and we knew it was attainable. Now that we have experience with this organism, we can go out and look at other bacteria that have this capability.”

In the future, the Center’s investments in synthetic biology, protein engineering, additive manufacturing and materials science may leverage these nanoparticles in innovative ways to develop new materials and manufacturing capabilities across the CCDC Enterprise.