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Johns Hopkins APL Biomanufacturing Breakthroughs Bolster National Security
Will Stone, a molecular biologist, experiments in APL’s biomanufacturing lab.
Credit: Johns Hopkins APL/Craig Weiman
Biomanufacturing — the use of microbial organisms to make materials and molecules — can help solve important security challenges facing the United States, including making supply chains more secure, strengthening the defense industrial base, and producing materials for warfighters wherever and whenever they need them.
Equipped with this understanding, researchers at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, are combining their technical expertise, creativity and national security acumen to put biomanufacturing to work, developing tangible solutions to solve these national challenges.
“We ultimately want to create bio-enabled devices that utilize the best of both worlds — biology and technology — to protect citizens, troops, our allies and the planet,” said Sarah Herman, who leads APL’s Biological and Chemical Sciences Program. “Before we can produce these systems at scale, however, we need to pinpoint desired biological components and understand how to integrate them into traditional systems. Several teams across the Laboratory are working to do just that.”
Bio-Enabled Materials and Equipment Development
One APL team is enhancing the capabilities of solid-state devices, such as cameras and sensors, by incorporating lifelike properties into them. From self-healing materials to organically powered sensors, biology can elevate technology’s effectiveness by providing unique characteristics.
“All organisms have evolved unique characteristics that allow them to thrive in their respective environments,” said Ryan McQuillen, a biophysicist and APL biomanufacturing researcher. “For example, cells adhere together to form tissues and organs, rattlesnakes have special receptors that allow them to track prey using heat signatures, and microbes can persist in some of the most extreme environments on Earth. Underlying all of these characteristics is a special class of biopolymers called proteins.”
Using synthetic biology, researchers can carefully control protein polymer sequences to tune their function, identify ways to purify and isolate them, and then understand how they can be embedded into materials and larger devices.
The team is developing a miniaturized thermal-sensing platform that uses only biological parts. The platform generates its own power using a light-driven proton pump, similar to those found in our own retinas; it senses heat signatures using snake-derived, heat-triggered receptors, and it converts those signatures into a downstream detectable output — all within in a small, fatty capsule. Such a platform could be used as a lightweight, low-power sensor for new night-vision devices.
“When we incorporate biology, we can address challenges that are impossible to solve with other domains of science,” McQuillen said. “Bio-enabled devices have the potential to revolutionize not just thermal technologies but also a variety of technologies that exist purely in solid-state electronics.”
A yellow-lipped green pit viper wraps around a tree limb in ​Thailand. Some snakes, including pit vipers, have heat-sensing organs that help them locate warm-blooded prey in total darkness by detecting infrared light. APL researchers are taking inspiration from these snakes and are developing a miniaturized thermal-sensing platform that uses snake-derived heat-triggered receptors.
Credit: Bigstock
Creating Critical Resources in the Field
Whether it’s in the depths of the ocean or at the farthest edges of the solar system, the U.S. is exploring and operating in environments that extend past the easy reach of conventional supply chains. But venturing out to such places requires essential goods that the Department of Defense (DoD) refers to as defense material priority areas: food, fuel, fitness, fabrication and firepower.
APL researchers are working to make these supplies on-site using engineered microbes that “upcycle” local materials. They’ve demonstrated processes that could enable the production of food from air and are tackling the production of other valuable resources, including materials for replacement parts and equipment.
“The DoD is quickly expanding its additive manufacturing capabilities to produce replacement parts in the field,” said Will Stone, an APL molecular biologist. “3D printers are being used on ships worldwide, but they still need the actual material that they’ll make the parts with.”
APL is studying polyhydroxyalkanoates, or PHAs — “green” plastics that many microorganisms naturally make as an energy reserve — as the basis for generating 3D-printable materials on-site from locally sourced materials. Depending on what they’re fed, the microorganisms will produce plastics with slightly different properties, from brittle to flexible, raising the possibility that PHA-based materials could be tailored for a variety of applications.
“Ships produce a lot of waste, everything from cardboard boxes to food scraps and trash, which is then often pitched into an incinerator and vented or compacted,” Stone said. “We want to tap into those waste streams, feed those [waste] gases to microbes instead, and have the microbes convert them into usable plastic.”
The team is refining ways to control which types of plastic are produced by the bacteria.
Eco-Friendly Plastic Waste Degradation
Waste products from the field offer another possible feedstock for microbes. Burning left-behind equipment and trash emits toxic chemicals that harm the environment and surrounding communities, so APL researchers are identifying alternative and eco-friendly methods to destroy trash that could further fuel biomanufacturing.
“We want to be prepared so that if a sponsor were to ask us which enzymes could decompose any waste product, such as plastic, or wood, or nylon, we will already have an understanding of how the enzymes work and how to identify which ones would be most effective in degrading a specific material,” said Claire Marie Filone, chief scientist in APL’s Biological Sciences Group.
Enzymes found in organisms have naturally evolved to degrade a wide range of materials, including biomaterials, plastics, fabrics and even metals. APL researchers are isolating and stabilizing these material-eating enzymes so that they may one day be delivered in a functional format to dissolve waste in the field.
Biologist Mark Gasser ventured on a multiyear bioprospecting trip to identify organisms with desirable decomposition abilities. His search led him to hunt for scraps of driftwood in which shipworms (tiny mollusks with long, worm-like bodies) live. For centuries, shipworms have been a nuisance to sailors, sinking vessels by eating holes in wooden hulls.
“The shipworm is fascinating because the enzymes that help digest wood aren’t initially present at the site of digestion: They’re actually made by symbiotic bacteria in their gills and then transported through their body to the stomach to help with digestion,” Gasser explained.
A piece of honeycombed driftwood, eaten by shipworms. Mark Gasser, an APL biologist, has studied the bacterial enzymes in shipworms that can degrade the strengthening component in wood and how they could be applied to future biodegradable mechanisms and tools.
Credit: Adobe Stock
The journey from gills to stomach means shipworms may have solved several problems that researchers are trying to understand — whether enzymes of interest can be separated from their hosts and, if so, how they can survive on their own.
After identifying and sequencing the symbiotic bacteria DNA in the shipworms, the researchers confirmed that the bacterial enzymes can degrade cellulose waste (the strengthening material in wood) in simulated military field conditions at accelerated rates compared with commercial enzymes. This is possibly because the enzymes are encapsulated in a fatty casing that amplifies and prolongs their degradation capabilities. They’ve also identified enzymes capable of degrading oil-based materials.
The team’s bioprospecting has likewise led to the development of a framework for evaluating a variety of natural enzymes and their abilities to decompose materials. The researchers sequenced microbe genomes, determined relevant pathways, evaluated microbial degradation of target material, and began to isolate the critical enzymes and other associated proteins.
“You can imagine there are a number of applications for this research,” Filone said. “Whether it’s degrading trash in the battlefield or destroying floating garbage patches in the ocean, it’s all focused on using natural tools and mechanisms to make the planet a cleaner place.”
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