Stronger national defense through biology

Speedier aircraft, more maneuverable submarines, tougher tanks - these and other technologies are prized by strategists in the U.S. Department of Defense, who are willing to spend substantial sums of money to spur their development.

David Kisailus, professor of materials science and engineering, is one of UC Irvine's top recipients of federal funding earmarked for national security innovations, having secured nearly $10 million from the Air Force Office of Scientific Research and the Army Research Office in recent years. His focus is terrestrial and marine creatures with exceptional properties that help them endure harsh environments.

"Over millions of years of evolution, some organisms have acquired physical characteristics and habits that help them survive in difficult conditions," says Kisailus, who's a Kavli Fellow of the National Academy of Sciences. "Our advantage as humans living in the 21^st century is that we don't have to wait hundreds of thousands or millions of years. We can quickly learn lessons from nature and translate them into engineered materials that work to our benefit in a variety of fields."

He receives substantial support from federal agencies, particularly those in the national security space and energy sector, Kisailus says, because officials there recognize his lab's ability to reveal fundamental scientific principles derived from nature in order to develop advanced materials that can transform the next generation of lightweight aircraft or stronger armor or even circumvent our nation's dependence on foreign entities for crucial minerals.

Inspiring organisms

Desert microbes

The Atacama Desert in Chile is one of the driest places on earth, but certain species of microbes have found a way to survive in this severe environment. Kisailus and his colleagues have studied how the bacteria secrete a biofilm that dissolves minerals, enabling them to obtain both water and elements that support their metabolic processes.

Kisailus has proposed mimicking the microbes with a novel technique aimed at sifting critical minerals, such as rare earth elements and lithium, from bulk soil. These substances are abundant everywhere on our planet, including waste tailings from mining sites, but are widely distributed and in trace amounts - think eye droppers, not shovels. Nonetheless, they are vital to our national security, so Kisailus wants to elicit the help of microbial miners to build up domestic sources of these vital substances.

He also believes that these simple yet hearty organisms can be sent to extremely inhospitable places to perform useful tasks. "If you want to build something on the moon, instead of going through the expense of having people do it, we could have robotic systems 3D-print media and then have the microbes reconfigure it into something of value," Kisailus explains. "This could be done without endangering human lives."

Diabolical ironclad beetle

In desert landscapes of the American Southwest, a small, unassuming insect has been quietly perfecting one of nature's most remarkable feats. The diabolical ironclad beetle, barely larger than a quarter, possesses an exoskeleton so tough it can survive being run over by a car. Kisailus and his colleagues have unlocked the mysteries of this tiny tank - and their discoveries could revolutionize everything from military armor to spacecraft design.

The secret lies in the beetle's elytra - modified forewings that have evolved into a solid protective shield. Using high-resolution microscopy and spectroscopic analysis, Kisailus and his team found that the beetle's armor consists of layers of chitin (a fibrous material) and proteins arranged in a unique, jigsaw puzzle-like configuration. When compressed, rather than snapping, the structure separates in layers, providing what Kisailus calls "graceful failure."

"When you break a puzzle piece, you expect it to separate at the neck, the thinnest part," he explains. "But we don't see that sort of catastrophic split with this species of beetle. Instead, it delaminates, providing for a more graceful failure of the structure."

This discovery has immediate applications for aerospace engineering. Traditional aircraft joints rely on rivets and fasteners - each representing a potential failure point. Kisailus' team has already created carbon fiber-reinforced composites that mimic the diabolical ironclad beetle's interlocking design and have proven stronger and tougher than current aerospace fasteners.

Mantis shrimp

Aquarium tanks in the laboratory of David Kisailus, UC Irvine professor of materials science and engineering, are home to mantis shrimp. Kisailus has been studying the extremely hard and resilient appendages that the crustaceans use to subdue prey and crush shells, rocks and other hard substances, an ability that helps the creatures survive. Kisailus draws inspiration from the shrimps' mighty punch to engineer materials with a broad range of applications, including many in national security. Steve Zylius / UC Irvine

While the ironclad beetle perfected defense, the mantis shrimp has mastered offense. These ancient crustaceans wield appendages called dactyl clubs that can move at over 50 mph, delivering devastating blows to prey and crushing shells, rocks and other hard substances, an ability that helps the creatures survive. What's remarkable isn't just the power - it's that these biological hammers show no damage after thousands of high-speed whacks.

Kisailus discovered that the clubs feature a uniquely designed combination of a nanoparticle coating and underlying architected biocomposite that absorbs and dissipates significant impact energy. The coating consists of bicontinuous spheres made of intertwined organic and inorganic nanocrystals - essentially biological Lego blocks that fracture and break during impact, protecting what's underneath.

The design principles in the mantis shrimp's coating are already inspiring new materials for protection against high-velocity ballistics. The blend of stiff inorganic and soft organic components in an interpenetrating network creates dramatic damping properties without compromising hardness - a rare combination that outperforms most metals and technical ceramics.

Below the coating is a precision-based architected biocomposite called a helicoid, which consists of sheets of organic fibers surrounded by minerals that are stacked upon each other but with each subsequent layer rotated a bit so that the entire structure resembles a spiral staircase. This architecture provides significant damage protection - reducing impact penetration depth by half compared to current aircraft designs - while dissipating enormous amounts of energy.

"Think about punching a wall a couple thousand times at those speeds and not breaking your fist," Kisailus marvels. "That's pretty impressive."

In addition to his activities that are funded by the federal government, Kisailus founded a startup company to implement mantis shrimp-inspired base plates for mortar launching systems and an armoring application for the Air Force. In another project with the Air Force, he's once again drawn from mantis shrimp designs to come up with ultralightweight protective cages for drones.

Innovations in the near term and further into the future

The convergence of biology, materials science and national security represents a new frontier in defense technology. Kisailus' work demonstrates that some of the most advanced solutions to modern challenges have already been perfected by nature. From beetle armor that could protect future aircraft to microbial miners that could build lunar bases, these biological blueprints offer pathways to technologies that seemed like science fiction just decades ago.

The results speak for themselves: materials that are stronger, lighter, more efficient and more resilient than anything human engineers have created from scratch. In Kisailus' vision, the future of national defense began in the distant evolutionary past and is now being perfected in his biomimetics laboratory on the UC Irvine campus.